Home About us Contact
|
Home About us Contact | ||
|
|
||
Shrew
Kinds of Shrew Selected AbstractsVirtuous Viragos: Female Heroism and Ethical Action in Shakespearean DramaLITERATURE COMPASS (ELECTRONIC), Issue 6 2010Unhae Langis Virtue, from the Latin vir for manly courage and strength, was the mark of male excellence in Renaissance culture. Embodying both physical and moral strength through the famous figure of Hercules, virtue took on other values of courtly gentility and political prudence as the medieval warrior society was gradually transformed into the modern state. In inverse proportion to the expansion of male virtue, the conception of the virago underwent a corresponding constriction and decline from a manlike, heroic woman to a scold. Encompassing both physical and moral excellence (OED 2a, 7), male virtue came to appropriate the heroic definition of virago, and female virtue, by Shakespeare's time, became confined to chastity (OED 2c). Challenging the traditions of male virtue and female monstrosity in Renaissance drama, this essay examines the virtuous viragos populating the Shakespearean canon, who present themselves as better models of ethical action than men, with whom virtue is etymologically and historically associated. This study examines two nuanced conceptions of female heroism and ethical action centering on the erotic and politic Cleopatra and the chaste, self-affirming Desdemona as virtuous viragos. Moreover, the notion of heroism, traditionally associated with tragedy, translates to the less exalted but more prudentially successful ethical action of viragos in Shakespeare's comedies such as The Taming of the Shrew. I argue that virtuous viragos attain their ethical stature against this male-inflected standard of tragic heroism even while calling for its dismantling and replacement with the more discerning framework of neo-Aristotelian virtue grounded on practical wisdom. [source] Female Characters on the Jacobean Stage Defying Type: When is a Shrew Not a Shrew?LITERATURE COMPASS (ELECTRONIC), Issue 4 2007Anna Kamaralli This essay won the 2006 Literature Compass Graduate Essay Prize, Seventeenth Century Section. Within the dramatic conventions of the Jacobean period one of the stock female character types that would have been familiar to the audience was the shrew: a woman, usually a wife, who is outspoken and argumentative. This article examines two plays written early in the seventeenth century, John Webster's The White Devil and William Shakespeare's The Winter's Tale, and considers their presentation of female characters who manifest behaviour that might be considered shrewish. It argues that the plays contain passages that frame a sophisticated attack on such misogynist classifications of the female. The characters in question do more than fail to be confined by the traditionally limited female types, they seem to deliberately call into question the existence of such types, and highlight their nature as artificially constructed and imposed, and inadequate to define the possibilities of womanhood. Both plays challenge the convention that silence in a woman should be equated with virtue by presenting situations where a woman's virtue demands that she speak. More particularly, they both mock the conventional Jacobean typing of shrewishness, the former by presenting good-wife-as-shrew, the latter by presenting shrew-as-oracle. [source] Changes in the food of British Barn Owls (Tyto alba) between 1974 and 1997MAMMAL REVIEW, Issue 2 2000R. Alasdair Love ABSTRACT Comparison of the results of a 1993,97 Barn Owl Tyto alba pellet survey with those of a similar survey from 1956,74 showed that Barn Owl diet had changed significantly. The primary differences were a widespread decrease in the percentage of Common Shrew Sorex araneus, combined with an increase in Pygmy Shrew Sorex minutus. The percentage of Wood and Yellow-necked mice Apodemus sylvaticus and A. flavicollis and Bank Vole Clethrionomys glareolus in the diet also increased. Changes in Barn Owl diet since 1974 were independent of land-class group, but were dependent upon region. This was due primarily to a large increase in the percentage of Apodemus spp. in Eastern England. Whilst the percentage of Pygmy Shrew in Barn Owl diet showed significant regional variation, there was no significant variation between land-class groups. The diversity of Barn Owl diet increased between 1974 and 1997, although it was still lower in 1997 than earlier in the century. This increase was dependent upon region, but independent of land-class group. The combined results of both surveys showed significant interland-class group variation in dietary diversity. Changes in diet are discussed in relation to the intensification of agriculture and other changes in land management since the 1970s. The effects on Barn Owls of these changes in prey abundance are discussed, particularly in relation to the decline in Barn Owl numbers during the twentieth century. [source] Immunohistochemical Localization of Inhibin and Steroidogenic Enzymes in the Ovary of Common Tree Shrew (Tupaia glis) and Northern Smooth-tailed Tree Shrew (Dendrogale murina)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 5 2000J. Kimura Summary To study the ovarian function of the Order Scandentia, the localization of inhibin and steroidogenic enzymes (3,-hydroxysteroid dehydrogenase/isomerase and aromatase) in the ovaries of common tree shrew (Tupaia glis) and northern smooth-tailed tree shrew (Dendrogale murina) was immunohistochemically analysed. As in the results reported for other mammals, inhibin ,-chain was localized in the follicular epithelium of secondary or Graafian follicles in the two species. The localization of aromatase in the ovary of these two species, however, was different. In the common tree shrew, the aromatase was localized in the thecal cells, whilst in other mammals it is localized in the granulosa cells. These results indicate that in the ovary of the common tree shrew, the oestradiol may be synthesized in the thecal cells. [source] The taming of the shrew milk teethEVOLUTION AND DEVELOPMENT, Issue 4 2008Elina Järvinen SUMMARY A characteristic feature of mammalian dentition is the evolutionary reduction of tooth number and replacement. Because mice do not replace teeth, here we used Sorex araneus, the common shrew, as a model to investigate the loss of tooth replacement. Historically, shrews have been reported to initiate the development of several, milk or deciduous teeth but these soon become rudimentary and only the replacement teeth erupt. Shrews thus offer a living example of a derived mammalian pattern where the deciduous tooth development is being suppressed. Based on histological and gene expression analyses of serial sections, we suggest that S. araneus has discernible tooth replacement only in the premolar 4 (P4) position. Both generations of teeth express Shh in the enamel knot and in the inner enamel epithelium. Nevertheless, the deciduous P4 (dP4) is reduced in size during embryogenesis and is eventually lost without becoming functional. Analysis of growth shows that P4 replaces the dP4 in a "double-wedge" pattern indicative of competitive replacement where the suppression of the deciduous tooth coincides with the initiation of its replacement. Because activator,inhibitor mechanisms have been implicated in adjacent mouse molars and in transgenic mice with continuous tooth budding, we suggest that evolutionary suppression of deciduous teeth may involve early activation of replacement teeth, which in turn begin to suppress their deciduous predecessors. [source] A pleasing consequence of Norway rat eradication: two shrew species recoverDIVERSITY AND DISTRIBUTIONS, Issue 3 2005Michel Pascal ABSTRACT Four to 10 years after the successful eradication of the Norway rat (Rattus norvegicus) from three islands of the Sept,Îles Archipelago and one in the Molène Archipelago (Brittany, France), the abundance index of the lesser white-toothed shrew (Crocidura suaveolens) increased by factors of 7,25, depending on the island and the year. Moreover, in the same region, the abundance index of the greater white-toothed shrew (Crocidura russula) on Tomé Island increased by factors of 9 and 17, one and two years after the Norway rat eradication, respectively. The maximum variation of the abundance index for the lesser white-toothed shrew during seven years on the rat-free island of Béniguet in the same region was a factor of only 2.5. Moreover, the distribution of the lesser white-toothed shrew on Bono island, restricted before the eradication to two steep areas with few rats, increased and encompassed virtually the entire island four years after rats disappeared. These results suggest strong detrimental interactions between the introduced Norway rat and the two Crocidura shrew species on temperate oceanic islands. However, our data do not indicate the ecological mechanisms at work in these interactions. The main reason this shrew recovery was detected after rat eradication was the inclusion in the eradication protocol of the evaluation of impacts on the local biota of eliminating alien species. The rigor of the sampling procedure was also crucial to this discovery. This example demonstrates that an eradication operation can be extremely useful for both scientists and managers if it is planned as a research project. [source] Generation recruitment and death of brain cells throughout the life cycle of Sorex shrews (Lipotyphla)EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2008Katarzyna Bartkowska Abstract Young shrews of the genus Sorex that are born in early summer reduce their body size before wintering, including a reduction of brain weight of 10,30%. In the spring they mature sexually, double their body weight and regain about half of the loss in brain weight. To investigate the mechanisms of brain weight oscillations we studied the rate of cell death and generation in the brain during the whole life cycle of the common shrew (Sorex araneus) and pygmy shrew (S. minutus). After weaning, shrews generate new brain cells in only two mammalian neurogenic zones and approximately 80% of these develop into neurones. The increase of the shrew brain weight in the spring did not depend on recruitment of new cells. Moreover, adult Sorex shrews did not generate new cells in the dentate gyri. Injections of 5-HT1A receptor agonists in the adult shrews induced neurogenesis in their dentate gyri, showing the presence of dormant progenitor cells. Generation of new neurones in the subventricular zone of the lateral ventricles and their recruitment to olfactory bulbs continued throughout life. TUNEL labelling showed that the rate of cell death in all brain structures, including the proliferation zones and olfactory bulb, was very low throughout life. We conclude that neither cell death nor recruitment significantly contributes to seasonal oscillations and the net loss of brain weight in the Sorex shrews. With the exception of dentate gyrus and olfactory bulb, cellular populations of brain structures are stable throughout the life cycle of these shrews. [source] Development of heterodont dentition in house shrew (Suncus murinus)EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 6 2007Atsushi Yamanaka Mammalian heterodont dentition comprises incisors, canines, premolars, and molars. Although there has been intensive research, the patterning of these specific tooth types has not yet been elucidated. In order for the gene expression data to be linked with tooth type determination, it is first necessary to determine precisely the incisor-, canine-, premolar-, and molar-forming regions in the jaw primordia. To accomplish this, we studied dentition development in the house shrew (Suncus murinus), which has retained all the tooth types, using three-dimensional reconstructions from serial histological sections and the Sonic hedgehog (Shh) expression patterns. Before the appearance of morphological signs of odontogenesis, Shh expression localized to the presumptive tooth-forming regions, in which the mesial and distal expression domains corresponded to the incisor- and premolar-forming regions, respectively. The upper incisor region was found to extend across the boundary between the frontonasal and the maxillary processes. The canine-forming regions later appeared in the intermediate portions of the maxillary and the mandibular processes. The molar-forming regions later appeared distal to the initially demarcated tooth-forming regions by secondary extension of the distal ends. The demarcation visualized by the Shh expression pattern in the jaw primordia of the house shrew probably represents the basic developmental pattern of mammalian heterodont dentition. [source] The taming of the shrew milk teethEVOLUTION AND DEVELOPMENT, Issue 4 2008Elina Järvinen SUMMARY A characteristic feature of mammalian dentition is the evolutionary reduction of tooth number and replacement. Because mice do not replace teeth, here we used Sorex araneus, the common shrew, as a model to investigate the loss of tooth replacement. Historically, shrews have been reported to initiate the development of several, milk or deciduous teeth but these soon become rudimentary and only the replacement teeth erupt. Shrews thus offer a living example of a derived mammalian pattern where the deciduous tooth development is being suppressed. Based on histological and gene expression analyses of serial sections, we suggest that S. araneus has discernible tooth replacement only in the premolar 4 (P4) position. Both generations of teeth express Shh in the enamel knot and in the inner enamel epithelium. Nevertheless, the deciduous P4 (dP4) is reduced in size during embryogenesis and is eventually lost without becoming functional. Analysis of growth shows that P4 replaces the dP4 in a "double-wedge" pattern indicative of competitive replacement where the suppression of the deciduous tooth coincides with the initiation of its replacement. Because activator,inhibitor mechanisms have been implicated in adjacent mouse molars and in transgenic mice with continuous tooth budding, we suggest that evolutionary suppression of deciduous teeth may involve early activation of replacement teeth, which in turn begin to suppress their deciduous predecessors. [source] Numerical fluctuations in the northern short-tailed shrew: evidence of non-linear feedback signatures on population dynamics and demographyJOURNAL OF ANIMAL ECOLOGY, Issue 2 2002Mauricio Lima Summary 1,We studied a fluctuating population of the northern short-tailed shrew (Blarina brevicauda) in the Appalachian Plateau Province of Pennsylvania, USA, spanning 21 years of monitoring. We analysed the pattern of annual temporal variation fitting both time-series models and capture,mark,recapture (CMR) statistical models for survival and recruitment rates. 2,We determined that non-linear first-order models explain almost 80% of the variation in annual per capita population growth rates. In particular, a non-linear self-excited threshold autoregressive (SETAR) model describes the time-series data well. Average snowfall showed positive and non-linear effects on population dynamics. 3,The CMR statistical models showed that a non-linear threshold model with strong effects of population density was the best one to describe temporal variation in survival rates. On the other hand, population density or climatic variables did not explain temporal variation in recruitment rates. Survival rates were high during the study period. Weekly changes in population size attributable to new recruits entering in the population fluctuate between 21% and 0%, while the changes in population size related to survival fluctuate between 79% and 100%. 4,Two important results arise from this study. First, non-linear models with first-order feedback appear to capture the essential features of northern short-tailed shrew dynamics and demography. Secondly, climate effects represented by snowfall appear to be small and non-linear on this insectivore. The population dynamics of this shrew in the Appalachian Plateau are determined apparently by a strong non-linear first-order feedback process, which is related to survival rates. 5,This study links population dynamics and demography by detecting the underlying demographic mechanisms driving population dynamics. The feedback structure of this shrew suggests the existence of population dynamics dominated by intraspecific competitive interactions, such as aggression, solitary nesting, non-overlapping home ranges and territoriality. [source] ORIGINAL ARTICLE: Extinction of the autochthonous small mammals of Mallorca (Gymnesic Islands, Western Mediterranean) and its ecological consequencesJOURNAL OF BIOGEOGRAPHY, Issue 6 2008Pere Bover Abstract Aim, To investigate the chronology, causes and consequences of the extinction of the autochthonous Pleistocene small mammals of Mallorca. Location, Mallorca (Gymnesic Islands, Balearics, Western Mediterranean). Methods, We have obtained the first direct 14C ages from the bone collagen of selected samples of two extinct endemic small mammals from Mallorca: the Balearic dormouse, Eliomys morpheus (Rodentia: Myoxidae) and the Balearic shrew, Asoriculus hidalgoi (Soricomorpha: Soricidae). We also present evidence for the absence of both endemics from the earliest Mallorcan archaeological sites and for the introduction of the garden dormouse, Eliomys quercinus, and the wood mouse, Apodemus sylvaticus. Combined information from direct dating of bone collagen of E. quercinus and A. sylvaticus and from cultural associations provides an adequate framework to establish the chronology of the faunal change and to compare it with the chronological information available on climatic change and the first arrival of humans on the islands. Results, The chronological record includes the latest evidence available for the survival of endemic species and the earliest introduction of small mammals into Mallorca. We present ,uncertainty periods for extinction' (UPEs) of both endemic mammals based on the chronology of their last occurrence and on the inferred timing of their extinction (restricted UPEs). Main conclusions, Possible causes for the extinction of autochthonous small mammals on Mallorca are discussed. Once we have discarded climatic causes, predation by invasive species, competition with newcomers and habitat deterioration, the introduction of diseases emerges as the most reasonable explanation for these extinctions. Based on the identification of changes in keystone species in Mallorcan ecosystems, we propose a tentative schedule of key ecological changes that have taken place over the past 5 millennia. [source] Ecomorphometric variation and sexual dimorphism in the common shrew (Sorex araneus)JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 6 2009T. A. WHITE Abstract We investigated the evolution of the biomechanics of the mandible in island and mainland populations of the common shrew on the west coast of Scotland. We predicted that climatic differences between populations should cause differences in prey composition leading to changes in the mechanical potential (MP) of the mandible. In females, MP was correlated with climate, with greater MP in warmer and drier habitats. In males, MP was significantly greater than in females but there was no relationship between male MP and climate. This led to increased sexual dimorphism in colder and wetter climates. The same pattern was found after a phylogenetic least squares analysis was conducted to account for shared phylogenetic history. We discuss possible reasons for this pattern, including male,male combat and the greater necessity of females to feed as efficiently as possible to meet their extremely high energy requirements during lactation. [source] Phylogeny, phylogeography, and geographic variation of Sylvisorex howelli (Soricidae), an endemic shrew of the Eastern Arc Mountains, TanzaniaJOURNAL OF ZOOLOGY, Issue 4 2005William T. Stanley Abstract The Eastern Arc Mountains of eastern Africa are notable for the high levels of endemism exhibited by various forest-dwelling organisms of this ancient montane archipelago. There has been virtually no assessment of the variation among populations of small mammal species living on these unique mountains, but recent faunal surveys have produced sufficient material to initiate such studies. Cranial morphometric and DNA sequence data were examined from six populations of Sylvisorex howelli Jenkins, 1984, an endemic shrew found in several different massifs of the Eastern Arc Mountains, to assess variation across the archipelago in the context of various hypotheses of historical biogeography. Twenty-two cranial measurements were analysed using principal components analysis. Age classes (based on tooth wear) and sex had little effect on the variation exhibited by the variables studied. Overall, specimens of S. howelli from the East Usambara Mountains are smaller than specimens from other known populations. The mitochondrial ND2 and 12S rRNA genes from representatives of each montane population of S. howelli in addition to several crocidurine taxa from eastern Africa and three soricine outgroup species were sequenced to assess phylogenetic relationships among these taxa. Neither maximum likelihood, maximum parsimony, nor Bayesian analyses support monophyly of the genus Sylvisorex, but S. howelli populations were consistently recovered as a well-supported clade. Over 40 individuals of S. howelli from six disjunct montane ranges, comprising the entire known distribution of the species, were sequenced for 504 base pairs of ND2 to investigate phylogeographic patterns. Phylogenetic analysis recovered six reciprocally monophyletic haplotype clades grouped by locality. Branch lengths are consistent with relatively long periods of isolation among populations from the Uluguru, Ukaguru, Nguru, Nguu, East Usambara and West Usambara Mountains, with low levels of diversity observed within each population. These results are interpreted within the historical context of the Eastern Arc Mountains. [source] Female Characters on the Jacobean Stage Defying Type: When is a Shrew Not a Shrew?LITERATURE COMPASS (ELECTRONIC), Issue 4 2007Anna Kamaralli This essay won the 2006 Literature Compass Graduate Essay Prize, Seventeenth Century Section. Within the dramatic conventions of the Jacobean period one of the stock female character types that would have been familiar to the audience was the shrew: a woman, usually a wife, who is outspoken and argumentative. This article examines two plays written early in the seventeenth century, John Webster's The White Devil and William Shakespeare's The Winter's Tale, and considers their presentation of female characters who manifest behaviour that might be considered shrewish. It argues that the plays contain passages that frame a sophisticated attack on such misogynist classifications of the female. The characters in question do more than fail to be confined by the traditionally limited female types, they seem to deliberately call into question the existence of such types, and highlight their nature as artificially constructed and imposed, and inadequate to define the possibilities of womanhood. Both plays challenge the convention that silence in a woman should be equated with virtue by presenting situations where a woman's virtue demands that she speak. More particularly, they both mock the conventional Jacobean typing of shrewishness, the former by presenting good-wife-as-shrew, the latter by presenting shrew-as-oracle. [source] Genetic diversity and population size: island populations of the common shrew, Sorex araneusMOLECULAR ECOLOGY, Issue 10 2007THOMAS A. WHITE Abstract Populations of many species are currently being fragmented and reduced by human interactions. These processes will tend to reduce genetic diversity within populations and reduce individual heterozygosities because of genetic drift, inbreeding and reduced migration. Conservation biologists need to know the effect of population size on genetic diversity, as this is likely to influence a population's ability to persist. Island populations represent an ideal natural experiment with which to study this problem. In a study of common shrews (Sorex araneus) on offshore Scottish islands, 497 individuals from 13 islands of different sizes and 6 regions on the mainland were trapped and genotyped at eight microsatellite loci. Previous genetic work had revealed that most of the islands in this study were highly genetically divergent from one another and the mainland. We found that most of the islands exhibited lower genetic diversity than the mainland populations. In the island populations, mean expected heterozygosity, mean observed heterozygosity and mean allelic richness were significantly positively correlated with log island size and log population size, which were estimated using habitat population density data and application of a Geographic Information System. [source] Genetic and karyotypic structure in the shrews of the Sorex araneus group: are they independent?MOLECULAR ECOLOGY, Issue 6 2006P. BASSET Abstract The species of the common shrew (Sorex araneus) group are morphologically very similar but exhibit high levels of karyotypic variation. Here we used genetic variation at 10 microsatellite markers in a data set of 212 individuals mostly sampled in the western Alps and composed of five karyotypic taxa (Sorex coronatus, Sorex antinorii and the S. araneus chromosome races Cordon, Bretolet and Vaud) to investigate the concordance between genetic and karyotypic structure. Bayesian analysis confirmed the taxonomic status of the three sampled species since individuals consistently grouped according to their taxonomical status. However, introgression can still be detected between S. antinorii and the race Cordon of S. araneus. This observation is consistent with the expected low karyotypic complexity of hybrids between these two taxa. Geographically based cryptic substructure was discovered within S. antinorii, a pattern consistent with the different postglaciation recolonization routes of this species. Additionally, we detected two genetic groups within S. araneus notwithstanding the presence of three chromosome races. This pattern can be explained by the probable hybrid status of the Bretolet race but also suggests a relatively low impact of chromosomal differences on genetic structure compared to historical factors. Finally, we propose that the current data set (available at http://www.unil.ch/dee/page7010_en.html#1) could be used as a reference by those wanting to identify Sorex individuals sampled in the western Alps. [source] Phylogeographical structure, postglacial recolonization and barriers to gene flow in the distinctive Valais chromosome race of the common shrew (Sorex araneus)MOLECULAR ECOLOGY, Issue 4 2002N. Lugon-Moulin Abstract Using one male-inherited and eight biparentally inherited microsatellite markers, we investigate the population genetic structure of the Valais chromosome race of the common shrew (Sorex araneus) in the Central Alps of Europe. Unexpectedly, the Y-chromosome microsatellite suggests nearly complete absence of male gene flow among populations from the St-Bernard and Simplon regions (Switzerland). Autosomal markers also show significant genetic structuring among these two geographical areas. Isolation by distance is significant and possible barriers to gene flow exist in the study area. Two different approaches are used to better understand the geographical patterns and the causes of this structuring. Using a principal component analysis for which testing procedure exists, and partial Mantel tests, we show that the St-Bernard pass does not represent a significant barrier to gene flow although it culminates at 2469 m, close to the highest altitudinal record for this species. Similar results are found for the Simplon pass, indicating that both passes represented potential postglacial recolonization routes into Switzerland from Italian refugia after the last Pleistocene glaciations. In contrast with the weak effect of these mountain passes, the Rhône valley lowlands significantly reduce gene flow in this species. Natural obstacles (the large Rhône river) and unsuitable habitats (dry slopes) are both present in the valley. Moreover, anthropogenic changes to landscape structures are likely to have strongly reduced available habitats for this shrew in the lowlands, thereby promoting genetic differentiation of populations found on opposite sides of the Rhône valley. [source] Phylogeography of the dusky shrew, Sorex monticolus (Insectivora, Soricidae): insight into deep and shallow history in northwestern North AmericaMOLECULAR ECOLOGY, Issue 5 2001John R. Demboski Abstract Phylogenetic relationships among the dusky shrew (Sorexmonticolus) and eight related species (S. bairdi, S. bendirii, S. neomexicanus, S.ornatus, S. pacificus, S. palustris, S. sonomae and S.vagrans) were assessed using sequences from the mitochondrial cytochrome b gene (801 bp). Analyses using parsimony and maximum likelihood revealed significant molecular variation not reflected in previous morphological studies of these species. Conversely, three morphologically defined species (S.bairdi, S.neomexicanusandS.pacificus) were poorly differentiated. SorexornatusandS.vagrans represented basal taxa for a more inclusive group that included: (i) a widespread Continental clade containing S.monticolus (Arizona to Alaska, including S. neomexicanus); (ii) a Coastal clade containing S.monticolus (Oregon to south-east Alaska, including S. bairdiandS. pacificus); (iii) the semiaquatic species (S. bendiriiandS. palustris); and (iv) S.sonomae. Additional subdivision was observed within the Continental clade corresponding to populations from the northern and southern Rocky Mountains. Average uncorrected sequence divergence between the Coastal and Continental clades was 5.3% (range 4.5,6.2%), which exceeds many interspecific comparisons within this species complex and within the genus Sorex. Lack of resolution of internal nodes within topologies suggests a deep history of rapid diversification within this group. Late Pleistocene/Holocene glacial perturbations are reflected in the shallow phylogeographic structure within these clades in western North America. Our results suggest also that S. monticolus is not monophyletic under current taxonomic nomenclature. This perspective on phylogeographic history was developed within a growing comparative framework for other organisms in western North America. [source] Non-invasive genetic identification of small mammal species using real-time polymerase chain reactionMOLECULAR ECOLOGY RESOURCES, Issue 6 2008S. MORAN Abstract DNA identification of non-invasive samples is a potentially useful tool for monitoring small mammal species. Here we describe a novel method for identifying five small mammal species: wood mouse, bank vole, common shrew, pygmy shrew and water shrew. Species-specific real-time polymerase chain reaction primers were designed to amplify fragments of the mitochondrial cytochrome b gene from hair and scat samples. We also amplified nuclear DNA from scats, demonstrating their potential as a source of DNA for population genetic studies. [source] Y chromosome microsatellite isolation from BAC clones in the greater white-toothed shrew (Crocidura russula)MOLECULAR ECOLOGY RESOURCES, Issue 1 2006LORI J. LAWSON HANDLEY Abstract We constructed a microsatellite library from four Crocidura russula Y chromosome-specific bacterial artificial chromosome (BAC) clones. Only one of eight microsatellites was male-specific, despite genome walking to obtain more flanking sequence and testing of 93 primer combinations. Potential reasons for this low success are discussed. The male-specific locus, CRY3, was genotyped in 90 males, including C. russula from across the species range and two related species. The large difference in CRY3 allele size between eastern and western lineages supports earlier reports of high divergence between them. Despite polymorphism of CRY3 in Morocco, only one allele was found throughout the whole of Europe, consistent with previous studies that suggest recent colonization of Europe from a small number of Moroccan founders. [source] Characterization of eight polymorphic microsatellites in the shrew Crocidura suaveolens and its application to the study of insular populations of the French Atlantic coastMOLECULAR ECOLOGY RESOURCES, Issue 3 2004CLAIR. Abstract We developed eight polymorphic microsatellite loci to study the natural populations of Crocidura suaveolens, the lesser white-toothed shrew. These loci are used in the study of insular populations of the French Atlantic coast where these shrews exhibit gigantism features that suggest an insular syndrome. These populations were threatened by the invasion of the rat Rattus norvegicus and the eradication of this alien pest in some islands was followed by a demographic expansion of the shrew populations. These first genetic results suggest that the shrew populations in the three studied islands are very differentiated. [source] Organization of the main olfactory bulbs of some mammals: Musk shrews, moles, hedgehogs, tree shrews, bats, mice, and ratsTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 1 2004Katsuko Kosaka Abstract We immunohistochemically examined the organization of the main olfactory bulbs (MOBs) in seven mammalian species, including moles, hedgehogs, tree shrews, bats, and mice as well as laboratory musk shrews and rats. We focused our investigation on two points: 1) whether nidi, particular spheroidal synaptic regions subjacent to glomeruli, which we previously reported for the laboratory musk shrew MOBs, are also present in other animals and 2) whether the compartmental organization of glomeruli and two types of periglomerular cells we proposed for the rat MOBs are general in other animals. The general laminar pattern was similar among these seven species, but discrete nidi and the nidal layer were recognized only in two insectivores, namely, the mole and laboratory musk shrew. Olfactory marker protein-immunoreactive (OMP-IR) axons extended beyond the limits of the glomerular layer (GL) into the superficial region of the external plexiform layer (EPL) or the nidal layer in the laboratory musk shrew, mole, hedgehog, and tree shrew but not in bat, mouse, and rat. We observed, in nidi and the nidal layer in the mole and laboratory musk shrew MOBs, only a few OMP-IR axons. In the hedgehog, another insectivore, OMP-IR processes extending from the glomeruli were scattered and intermingled with calbindin D28k-IR cells at the border between the GL and the EPL. In the superficial region of the EPL of the tree shrew MOBs, there were a small number of tiny glomerulus-like spheroidal structures where OMP-IR axons protruding from glomeruli were intermingled with dendritic branches of surrounding calbindin D28k-IR cells. Furthermore, we recognized the compartmental organization of glomeruli and two types of periglomerular cells in the MOBs of all of the mammals we examined. These structural features are therefore considered to be common and important organizational principles of the MOBs. J. Comp. Neurol. 472:1,12, 2004. © 2004 Wiley-Liss, Inc. [source] Immunohistochemical Localization of Inhibin and Steroidogenic Enzymes in the Ovary of Common Tree Shrew (Tupaia glis) and Northern Smooth-tailed Tree Shrew (Dendrogale murina)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 5 2000J. Kimura Summary To study the ovarian function of the Order Scandentia, the localization of inhibin and steroidogenic enzymes (3,-hydroxysteroid dehydrogenase/isomerase and aromatase) in the ovaries of common tree shrew (Tupaia glis) and northern smooth-tailed tree shrew (Dendrogale murina) was immunohistochemically analysed. As in the results reported for other mammals, inhibin ,-chain was localized in the follicular epithelium of secondary or Graafian follicles in the two species. The localization of aromatase in the ovary of these two species, however, was different. In the common tree shrew, the aromatase was localized in the thecal cells, whilst in other mammals it is localized in the granulosa cells. These results indicate that in the ovary of the common tree shrew, the oestradiol may be synthesized in the thecal cells. [source] Biogeography and diversity among montane populations of mouse shrew (Soricidae: Myosorex) in TanzaniaBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2010WILLIAM T. STANLEY We assess variation in morphological and molecular characters among three species of Myosorex (the mouse shrew) ,Myosorex geata, Myosorex kihaulei, and Myosorex zinki, as a means to test previously proposed biogeographic hypotheses for Tanzanian ,sky islands' and systematic hypotheses for Tanzanian mouse shrews. We analyse 17 cranial and dental variables using multivariate statistics and perform phylogenetic and phylogeographic analyses on sequences of mitochondrial and nuclear DNA; samples are drawn from every known Tanzanian population of Myosorex. Morphometric and phylogenetic analyses reveal that M. zinki is distinct, but that currently isolated populations of M. geata and M. kihaulei are relatively similar to one another, and may not have been isolated over geological time scales. Analyses of molecular variance identify statistically significant, but limited, genetic variation within and between isolated populations of M. geata and M. kihaulei. Between two putative regional biogeographic boundaries, greater genetic variation is explained by grouping populations on either side of the Ruaha River than by grouping populations on either side of the Makambako Gap. Our results are in agreement with recent studies illustrating the close relationship between faunas of the Southern Highlands and southern Eastern Arc Mountains, diminishing the apparent importance of the Makambako Gap as a historical biogeographic barrier. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 669,680. [source] At the foot of the shrew: manus morphology distinguishes closely-related Cryptotis goodwini and Cryptotis griseoventris (Mammalia: Soricidae) in Central AmericaBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2010NEAL WOODMAN Small-eared shrews (Mammalia, Soricidae) of the New World genus Cryptotis are distributed from eastern North America to the northern Andes of South America. One well-defined clade in this genus is the Central American Cryptotis mexicana group, whose members are set off from other species in the genus by their variably broader fore feet and more elongate and broadened fore claws. Two species in the C. mexicana group, Cryptotis goodwini Jackson and Cryptotis griseoventris Jackson, inhabit highlands in Guatemala and southern Mexico and are presumed to be sister species whose primary distinguishing feature is the larger body size of C. goodwini. To better characterize these species and confirm the identification of recently-collected specimens, we obtained digital X-ray images of the manus from large series of dried skins of both species. Measurements of the metacarpals and phalanges successfully separated most specimens of C. goodwini and C. griseoventris. These measurements also show that the fore feet of C. griseoventris from Chiapas, Mexico, are morphologically distinct from those of members of the species inhabiting Guatemala. Univariate, bivariate, and multivariate analyses indicate that fore foot characters are more conservative within species of the C. mexicana group than are cranio-mandibular characters. Patterns of evolution of fore foot characters that superficially appear to be linear gradations are actually more complex, illustrating individual evolutionary trajectories. No claim to original US government works. Journal compilation © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 118,134. [source] Genetic variation in Irish pygmy shrews Sorex minutus (Soricomorpha: Soricidae): implications for colonization historyBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2009ALLAN D. MCDEVITT The status of the pygmy shrew (Sorex minutus L.) as a native or an introduced species in Ireland has been subject to much debate. To examine this and other aspects of the colonization history of the Irish pygmy shrew, genetic variation was determined in 247 pygmy shrews collected throughout Ireland, using mitochondrial control region sequences and five polymorphic microsatellite loci. Genetic diversity was low for both types of marker. The median-joining network for control region sequences was star-like, suggesting that the colonization of Ireland involved a small number of founders and rapid population expansion thereafter; this was supported by other statistics. Molecular dating with both mitochondrial DNA and microsatellite data is consistent with a human introduction. This would have been several thousand years ago; a recent colonization within historical times can be ruled out. This is the first detailed population genetic study of the pygmy shrew anywhere in its range. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 918,927. [source] The colonization of Scottish islands by the common shrew, Sorex araneus (Eulipotyphla: Soricidae)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2008THOMAS A. WHITE In this paper we apply molecular methods to study the colonization of islands off the west coast of Scotland by the common shrew (Sorex araneus L.), and current gene flow. We collected 497 individuals from 13 islands of the Inner Hebrides and Clyde Island groups and six mainland regions. Individuals were genotyped at eight microsatellite loci, and the mitochondrial cytochrome b sequence (1140 base pairs) was obtained for five individuals from each island/mainland region. Based on these molecular data, island colonization apparently proceeded directly from the mainland, except for Islay, for which Jura was the most likely source population. Raasay may also have been colonized by island hopping. Most island populations are genetically very distinct from the mainland populations, suggesting long periods of isolation. Two exceptions to this are the islands of Skye and Seil, which are geographically and genetically close to the mainland, suggesting in each case that there has been long-term gene flow between these islands and the mainland. We consider possible methods of island colonization, including human-mediated movement, swimming, and land and ice bridges. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 94, 797,808. [source] Taming of the shrew,engineering the morphology of filamentous fungi for improved production performanceBIOTECHNOLOGY & BIOENGINEERING, Issue 6 2010Article first published online: 24 FEB 2010 No abstract is available for this article. [source] The taming of the shrew?ACTA OPHTHALMOLOGICA, Issue 5 2009The immunology of corneal transplantation Abstract. Corneal transplantation, first reported a century ago, is the oldest and most frequent form of solid tissue transplantation. Although keratoplasty is also considered as the most successful transplant procedure, several studies indicate that the long term survival of corneal grafts is even lower than that of transplanted parenchymatous organs. Despite the immune privilege enjoyed by the cornea and anterior segment of the eye, immunologic graft rejection is a major limitation to corneal transplantation. This review gives an update on corneal immunobiology and the mechanisms of corneal graft rejection, focusing on antigen presentation, as well as on the molecular and cellular mediators of this particular immune response. [source] Long-term biomechanical properties of rabbit sclera after collagen crosslinking using riboflavin and ultraviolet A (UVA)ACTA OPHTHALMOLOGICA, Issue 2 2009Gregor Wollensak Abstract. Purpose:, Scleral crosslinking by the photosensitizer riboflavin and ultraviolet A (UVA) has been shown to increase significantly the scleral biomechanical rigidity and might therefore become a possible sclera-based treatment modality for progressive myopia. In the present study, the long-term effect of the new crosslinking method on biomechanical properties was investigated in the rabbit sclera. Methods:, A 10 × 10 mm sector of the equatorial sclera of nine Chinchilla rabbit eyes was treated in vivo using a UVA double diode of 370 nm with a surface irradiance of 3 mW/cm2 and application of 0.1% riboflavin-5-phosphate drops as photosensitizer for 30 min. Three days, 4 months and 8 months postoperatively, biomechanical stress,strain measurements of the treated scleral strips were performed and compared to contralateral control sclera using a microcomputer-controlled biomaterial tester. In addition, routine histological controls were performed. Results:, Following the crosslinking treatment, Young's modulus was increased by 320% after 3 days, 277% after 4 months and 502% after 8 months, and ultimate stress by 341% after 3 days, 131% after 4 months and 213.8% after 8 months versus the controls. The decrease in ultimate strain was between 24% and 44.8%. On histology, no tissue damage was detected. Conclusion:, Our new method of scleral collagen crosslinking proved very effective and constant over a time interval of up to 8 months in increasing the scleral biomechanical strength. Therefore, the new treatment might become an option for strengthening scleral tissue in progressive myopia and other conditions associated with weakened sclera. There were no side-effects on the retina or retinal pigment epithelium. The new crosslinking treatment could now be tested in a suitable myopia model (like the tree shrew) and finally in human eyes. [source] | |||||||||||||||||||||||||||||||||||||