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The tapeworm Proteocephalus macrocephalus (Creplin, 1825), a parasite of the eel Anguilla anguilla, was characterised using morphological and genetic characters. The species is morphologically typified mainly by features of the scolex (i.e. shape and size of an apical organ which is formed early during the development in an intermediate host) and strobila (i.e. regularly rectangular proglottides, morphology of the vagina and anterior position of the seminal receptacle). Genetically, P. macrocephalus was compared with two congeners, P. percae and P. exiguus. Characters enabling differentiation of P. macrocephalus were as follows: fixed allelic differences at Got, Pgm and Gapdh loci, metrical features of chromosomes Nos 1, 2 and 7, and species-specific fragments obtained by RAPD method using 13 random primers. 相似文献
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Tortricini is a cosmopolitan tribe of the subfamily Tortricinae of the lepidopteran family Tortricidae. The most recent systematic of Tortricini are based on the external morphology of imagines and the structure of their genital organs. The present paper is the first comparative molecular study of the representatives of this tribe. We examined DNA variation in a 606 bp fragment of COI mtDNA obtained from 23 species of Tortricini and two representatives of other tribes (Archips podanus of Archipini and Aethes hartmanniana of Cochylini). The position of Spatalistis, Tortrix, Aleimma and Acleris, and some groupings of species within Acleris were confirmed by molecular data, including the synonymization of Croesia and Phylacophora with Acleris. The positions of a few groupings of the Acleris species remain unresolved. 相似文献
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Guler GD Liu H Vaithiyalingam S Arnett DR Kremmer E Chazin WJ Fanning E 《The Journal of biological chemistry》2012,287(9):6469-6481
Maintenance of genomic stability in proliferating cells depends on a network of proteins that coordinate chromosomal replication with DNA damage responses. Human DNA helicase B (HELB or HDHB) has been implicated in chromosomal replication, but its role in this coordinated network remains undefined. Here we report that cellular exposure to UV irradiation, camptothecin, or hydroxyurea induces accumulation of HDHB on chromatin in a dose- and time-dependent manner, preferentially in S phase cells. Replication stress-induced recruitment of HDHB to chromatin is independent of checkpoint signaling but correlates with the level of replication protein A (RPA) recruited to chromatin. We show using purified proteins that HDHB physically interacts with the N-terminal domain of the RPA 70-kDa subunit (RPA70N). NMR spectroscopy and site-directed mutagenesis reveal that HDHB docks on the same RPA70N surface that recruits S phase checkpoint signaling proteins to chromatin. Consistent with this pattern of recruitment, cells depleted of HDHB display reduced recovery from replication stress. 相似文献
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Parmentier E Gennotte V Focant B Goffinet G Vandewalle P 《Proceedings. Biological sciences / The Royal Society》2003,270(1530):2301-2308
Sound production in carapid fishes results from the action of extrinsic muscles that insert into the swim bladder. Biochemical, histochemical and morphological techniques were used to examine the sonic muscles and compare them with epaxial muscles in Carapus acus. Sonic fibres are thicker than red and thinner than white epaxial fibres, and sonic fibres and myofibrils exhibit an unusual helicoidal organization: the myofibrils of the centre are in a straight line whereas they are more and more twisted towards the periphery. Sonic muscles have both features of red (numerous mitochondria, high glycogen content) and white (alkali-stable ATPase) fibres. They differ also in the isoforms of the light chain (LC3) and heavy chain (HC), in having T tubules at both the Z-line and the A-I junction and in a unique parvalbumin isoform (PAI) that may aid relaxation. All these features lead to the expression of two assumptions about sound generation: the sonic muscle should be able to perform fast and powerful contractions that provoke the forward movement of the forepart of the swim bladder and the stretching and "flapping" of the swim bladder fenestra; the helicoidal organization allows progressive drawing of the swim bladder fenestra which emits a sound when rapidly released in a spring-like manner. 相似文献
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Stevens JD Roalson EH Skinner MK 《Differentiation; research in biological diversity》2008,76(9):1006-1022
A phylogenetic analysis of seven different species (human, mouse, rat, worm, fly, yeast, and plant) utilizing all (541) basic helix-loop-helix (bHLH) genes identified, including expressed sequence tags (EST), was performed. A super-tree involving six clades and a structural categorization involving the entire coding sequence was established. A nomenclature was developed based on clade distribution to discuss the functional and ancestral relationships of all the genes. The position/location of specific genes on the phylogenetic tree in relation to known bHLH factors allows for predictions of the potential functions of uncharacterized bHLH factors, including EST's. A genomic analysis using microarrays for four different mouse cell types (i.e. Sertoli, Schwann, thymic, and muscle) was performed and considered all known bHLH family members on the microarray for comparison. Cell-specific groups of bHLH genes helped clarify those bHLH genes potentially involved in cell specific differentiation. This phylogenetic and genomic analysis of the bHLH gene family has revealed unique aspects of the evolution and functional relationships of the different genes in the bHLH gene family. 相似文献
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Fabrizio Stefani Francesca Benzoni Michel Pichon Carlotta Cancelliere Paolo Galli 《Zoologica scripta》2008,37(1):71-91
The Indo-Pacific coral genus Psammocora Dana (1 846) has never been formally revised, and its phylogeny has only been partially explored. Several synonymies have been proposed for the 11 nominal species which have highly plastic branching growth forms. In the present study, the definition of genetic and morphologic boundaries among three currently recognized branching morpho-species, Psammocora stellata , Psammocora contigua and Psammocora obtusangula , is addressed through a joint morphometric and molecular study using corallite and branch measurements, and a portion of the β-tubulin gene as a marker. The results show a morphological and partial phylogenetic distinction between P. stellata specimens and a complex composed of P. contigua and P. obtusangula , which is interpreted as a synonym species of P. contigua. Among the factors that could be responsible for the lack of reciprocal monophyly of the three species, hybridization is considered the most likely, due to the presence of interspecific recombinant sequences. Type material of nominal species of branching Psammocora is examined and classified based on genetically defined groups, and compared with synonym in the literature. Among the morphological characters used, corallite variables were best for discriminating between the two lineages and allow recognition of putative hybrid specimens. Psammocora stellata is reported for the first time in the western Indian Ocean (Mayotte), thus greatly extending its known distribution range. Finally, a hybrid swarm is identified in the Arabo-Persian Gulf, while no genetic structure is detected elsewhere in the Indo-Pacific region. 相似文献
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Abraham RT 《Current biology : CB》2005,15(4):R139-R141
The target of rapamycin (TOR) protein kinase is centrally involved in the coordination of cell growth and proliferation with the availability of growth factors and nutrients. Two recent reports have illuminated a mechanism whereby hypoxic stress dampens TOR signaling in metazoan cells. 相似文献
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Sarmiento R Bonginelli P Cacciamani F Salerno F Gasparini G 《The International journal of biological markers》2008,23(2):96-110
Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. GISTs represent a distinct category of tumors characterized by oncogenic mutations of the KIT receptor tyrosine kinase in a majority of patients. KIT is useful not only for the diagnosis but also for targeted therapy of this disease. Imatinib, a tyrosine kinase inhibitor, is widely used in advanced and metastatic GISTs. This agent revolutionized the treatment strategy of advanced disease and is being tested in the neoadjuvant and adjuvant settings with encouraging results. New therapeutic agents like sunitinib have now been approved, enriching the treatment scenario for imatinib-resistant GISTs. The present review reports on the peculiar characteristics of this disease through its biology and molecular patterns, focusing on the predictive value of KIT mutations and their correlation with clinical outcome as well as on the activity of and resistance to approved targeted drugs. 相似文献
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Mura Graziella; Baxevanis Athanasios D.; Lopez German Medina; Hontoria Francisco; Kappas Ilias; Moscatello Salvatore; Fancello Giovanni; Amat Francisco; Abatzopoulos Theodore J. 《Journal of plankton research》2005,27(9):895-907
A parthenogenetic Artemia population from Torre Colimena, southernItaly, originally reported in 1998, is characterized by a multidisciplinaryapproach including cyst and naupliar biometry, morphometry ofadults, scanning electron microscopy (SEM) of brood pouch, cytogeneticsand 16S rRNA PCR-RFLP analysis. We confirmed parthenogeneticstatus, inferred ploidy level and determined phenotypic andmolecular relationships of this population through comparisonswith other asexual Artemia strains as well as bisexual speciesfound (A. salina) or introduced (A. franciscana) in the Mediterraneanbasin. Cyst and naupliar sizes for Torre Colimena are amongthe smallest recorded for asexual Artemia while the oppositeis true for chorion thickness. Discriminant analysis of adultbody measurements shows increased differentiation (89.5% forthe first four out of the twelve functions produced) from tetraploidparthenogenetic strains and bisexual species (A. salina andA. franciscana). Scanning electron micrographs of brood pouchreveal the characteristic morphology of asexual strains, whilechromosome observations of instar-I nauplii unequivocally establishdiploidy. Restriction patterns give evidence that the TorreColimena population shares an identical set of mitochondrialDNA (mtDNA) polymorphisms with a diploid Spanish parthenogeneticstrain and it is well differentiated from other tetraploid aswell as bisexual auto- and allochthonous strains (A. salinaand A. franciscana) from the Mediterranean. The present studymay serve as a reference methodological framework for multidisciplinarycharacterizations and biodiversity assessments in the genusArtemia. 相似文献
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R. L. H. DENNIS W. R. WILLIAMS T. G. SHREEVE 《Zoological Journal of the Linnean Society》1991,101(1):1-49
Multivariate analyses of 393 butterfly species over 85 geographical areas (R- and Q-data matrices) in Europe and North Africa have produced a consistent pattern of faunal structures (units and regions). Prominent features to emerge are the latitudinal zonation of geographical units and the division of the Mediterranean into western and eastern components; southwards in Europe, endemicity increases whereas faunal structures decrease in spatial dimensions. Central Europe–from the Urals to the British Isles–forms a single large faunal structure (extent unit and region). A model has been constructed to account for Pleistocene evolutionary changes and endemism in European butterflies and for the east-west taxonomic divisions in the extent faunal structure which dominates central Europe. Periodic Pleistocene climatic changes have resulted in cycles of population extinction, isolation, evolution and migration, but the nature and timing of events has depended on the environmental tolerances of species belonging to different faunal units. During Pleistocene glaciations, southern species have been relatively static and more isolated and have evolved independently. By comparison, northern species have been more mobile and have migrated over large distances. Contact and hybrid zones among cosmopolitan species in northern Europe are probably of some antiquity. They result from persistent survival and isolation of refuge populations in the west and east Mediterranean during glacial phases; dispersal from these refuges leads to their regeneration during each interglacial. 相似文献
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Timo van Eldijk Gerard Goris Adam Haarhuis Jos Lankamp Herman Winkelhorst Jelle Reumer André Nel Torsten Wappler 《Pal?ontologische Zeitschrift》2017,91(2):185-194
The Palaeozoic–Mesozoic transition is characterized not only by the most massive Phanerozoic mass extinction at the end of the Permian period, but also its extensive aftermath and a prolonged period of major biotal recovery during the succeeding Middle to Late Triassic. Particularly, Anisian insect species from units of the Lower to Middle Muschelkalk from the Central European Basin are rare. The specimens described here originated from the Anisian Wellenkalk facies (Lower Muschelkalk), Vossenveld Formation of the Winterswijk quarry, The Netherlands, and from the orbicularis Member (lowermost Middle Muschelkalk, Anisian) of Esperstedt near Querfurt (Saxony-Anhalt). Thus, the described insect remains from Winterwijk and Esperstedt expand our knowledge about Middle Triassic terrestrial arthropod communities and their palaeodiversity. A new species of Chauliodites (C. esperstedti sp. nov) is introduced. 相似文献
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Paleontological Journal - The Oxfordian–Kimmeridgian Cerithiopsidae, represented by two genera Cosmocerithium Cossmann, 1906 and Dragonia gen. nov. are re-investigated. Three species (C.... 相似文献
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High hydrostatic pressure (HHP) exerts diverse effects on microorganisms, leading to stress response and cell death. While inactivation of microorganisms by lethal HHP is well investigated in the context of food preservation and the hygienic safety of minimal food processes, sublethal HHP stress response and its effect on adaptation and cross-protection is less understood. In this study, the HHP stress response of Lactobacillus sanfranciscensis was characterized and compared with cold, heat, salt, acid and starvation stress at the proteome level by using 2-DE so as to provide insight into general versus specific stress responses. Sixteen proteins were found to be affected by HHP and were identified by using N-terminal amino acid sequencing and MS. Only one slightly increased protein was specific to the HHP response and showed homology to a clp protease. The other proteins were influenced by most of the investigated stresses in a similar way as HHP. The highest similarity in the HHP proteome was found to be with cold- and NaCl-stressed cells, with 11 overlapping proteins. At the proteome level, L. sanfranciscensis appears to use overlapping subsets of stress-inducible proteins rather than stereotype responses. Our data suggest that a specific pressure response does not exist in this bacteria. 相似文献