2,126 research outputs found

    Організаційно-педагогічні умови підготовки майбутнього педагога-музиканта в системі неперервної освіти

    Get PDF
    У статті досліджуються організаційно-педагогічні умови підготовки майбутнього педагога-музиканта в системі неперервної освіти.В статье исследуются организационно-педагогические условия подготовки будущего педагога-музыканта в системе непрерывного образования

    Поліетилен як наймасовіша пластмаса у виробництві упаковки

    Get PDF
    Delta/Notch (Dl/N) signalling is involved in the gene regulatory network underlying the segmentation process in vertebrates and possibly also in annelids and arthropods, leading to the hypothesis that segmentation may have evolved in the last common ancestor of bilaterian animals. Because of seemingly contradicting results within the well-studied arthropods, however, the role and origin of Dl/N signalling in segmentation generally is still unclear. In this study, we investigate core components of Dl/N signalling by means of gene expression analysis in the onychophoran Euperipatoides kanangrensis, a close relative to the arthropods. We find that neither Delta or Notch nor any other investigated components of its signalling pathway are likely to be involved in segment addition in onychophorans. We instead suggest that Dl/N signalling may be involved in posterior elongation, another conserved function of these genes. We suggest further that the posterior elongation network, rather than classic Dl/N signalling, may be in the control of the highly conserved segment polarity gene network and the lower-level pair-rule gene network in onychophorans. Consequently, we believe that the pair-rule gene network and its interaction with Dl/N signalling may have evolved within the arthropod lineage and that Dl/N signalling has thus likely been recruited independently for segment addition in different phyla

    The hatching larva of the priapulid worm Halicryptus spinulosus

    Get PDF
    Despite their increasing evolutionary importance, basic knowledge about the priapulid worms remains limited. In particular, priapulid development has only been partially documented. Following previous description of hatching and the earliest larval stages of Priapulus caudatus, we here describe the hatching larva of Halicryptus spinulosus. Comparison of the P. caudatus and the H. spinulosus hatching larvae allows us to attempt to reconstruct the ground pattern of priapulid development. These findings may further help unravelling the phylogenetic position of the Priapulida within the Scalidophora and hence contribute to the elucidation of the nature of the ecdysozoan ancestor

    A review of the correlation of tergites, sternites, and leg pairs in diplopods

    Get PDF
    In some arthropods there is a discrepancy in the number of dorsal tergites compared to the number of ventral sternites and leg pairs. The posterior tergites of the Diplopoda (millipedes) each cover two sternites and two pairs of legs. This segment arrangement is called diplosegmentation. The molecular nature of diplosegmentation is still unknown. There are even conflicting theories on the way the tergites and sternites/leg pairs should be correlated to each other. The different theories are based either on embryological analyses or on studies of the adult morphology and turned out to be not compatible with each other. We have previously used the expression patterns of segmentation genes in the pill millipede Glomeris marginata (Myriapoda: Diplopoda) to study millipede segmentation. Here we review the existing models on the alignment of tergites and leg pairs in millipedes with special emphasis on the implications the gene expression data have on the debate of tergite and leg pair assignment in millipedes. The remarkable outcome of the gene expression analysis was that (1) there is no coupling of dorsal and ventral segmentation and, importantly, that (2) the boundaries delimiting the tergites do neither correlate to the embryonic boundaries of the dorsal embryonic segments nor to the boundaries of the ventral embryonic segments. Using these new insights, we critically reinvestigated the correlation of tergites, sternites, and leg pairs in millipedes. Our model, which takes into account that the tergite boundaries are different from the dorsal embryonic segment boundaries, provides a solution of the problem of tergite to sternite/leg pair correlation in basal milipedes with non-fused exoskeletal elements and also has implications for derived species with exoskeletal rings. Moreover, lack of coupling of dorsal and ventral segmentation may also explain the discrepancy in numbers of dorsal tergites and ventral leg pairs seen in some other arthropods

    Expression of collier in the premandibular segment of myriapods: support for the traditional Atelocerata concept or a case of convergence?

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>A recent study on expression and function of the ortholog of the <it>Drosophila collier </it>(<it>col</it>) gene in various arthropods including insects, crustaceans and chelicerates suggested a <it>de novo </it>function of <it>col </it>in the development of the appendage-less intercalary segment of insects. However, this assumption was made on the background of the now widely-accepted Pancrustacea hypothesis that hexapods represent an in-group of the crustaceans. It was therefore assumed that the expression of <it>col </it>in myriapods would reflect the ancestral state like in crustaceans and chelicerates, i.e. absence from the premandibular/intercalary segment and hence no function in its formation.</p> <p>Results</p> <p>We find that <it>col </it>in myriapods is expressed at early developmental stages in the same anterior domain in the head, the parasegment 0, as in insects. Comparable early expression of <it>col </it>is not present in the anterior head of an onychophoran that serves as an out-group species closely related to the arthropods.</p> <p>Conclusions</p> <p>Our findings suggest either that i) the function of <it>col </it>in head development has been conserved between insects and myriapods, and that these two classes of arthropods may be closely related supporting the traditional Atelocerata (or Tracheata) hypothesis; or ii) alternatively <it>col </it>function could have been lost in early head development in crustaceans, or may indeed have evolved convergently in insects and myriapods.</p

    Публікації ХVІІІ - поч. ХХІ ст. про центральноукраїнські археологічні пам’ятки в Ермітажі

    Get PDF
    (UA) 1764 р. вийшла публікація Г. Міллера про наслідки перших археологічних розкопок в Україні. Виявлений тоді Литий скарб потрапив до Кунсткамери, а потім – до Ермітажу. Наступні автори вивчали, характеризували цю колекцію, виходячи з отриманих нових даних скіфологією. З ’являлася у світ інформація й про інші надходження до Ермітажу з території, яка сьогодні входить до Кіровоградщини. Ці публікації можуть стати певними свідченнями для обґрунтування постановки питання повернення історичних художніх цінностей з-за кордону до музейного фонду України.(EN) In 1764 the publication of G. Muller went out about the consequences of the first archaeological excavations in Ukraine. Poured treasure is educed then got to Cabinet of curiosities, and then to the Hermitage. Next authors studied, characterized this collection, coming from the obtained new data, as scythology. Information was published about other receivabless to the Hermitage from territory that is today included to the Kirovohrad area. These publications can become certain certificates for the ground of statement of a question of return of historical artistic values in the museum fund of Ukraine

    Expression of myriapod pair rule gene orthologs

    Get PDF
    Background Segmentation is a hallmark of the arthropods; most knowledge about the molecular basis of arthropod segmentation comes from work on the fly Drosophila melanogaster. In this species a hierarchic cascade of segmentation genes subdivides the blastoderm stepwise into single segment wide regions. However, segmentation in the fly is a derived feature since all segments form virtually simultaneously. Conversely, in the vast majority of arthropods the posterior segments form one at a time from a posterior pre-segmental zone. The pair rule genes (PRGs) comprise an important level of the Drosophila segmentation gene cascade and are indeed the first genes that are expressed in typical transverse stripes in the early embryo. Information on expression and function of PRGs outside the insects, however, is scarce. Results Here we present the expression of the pair rule gene orthologs in the pill millipede Glomeris marginata (Myriapoda: Diplopoda). We find evidence that these genes are involved in segmentation and that components of the hierarchic interaction of the gene network as found in insects may be conserved. We further provide evidence that segments are formed in a single-segment periodicity rather than in pairs of two like in another myriapod, the centipede Strigamia maritima. Finally we show that decoupling of dorsal and ventral segmentation in Glomeris appears already at the level of the PRGs. Conclusions Although the pair rule gene network is partially conserved among insects and myriapods, some aspects of PRG interaction are, as suggested by expression pattern analysis, convergent, even within the Myriapoda. Conserved expression patterns of PRGs in insects and myriapods, however, may represent ancestral features involved in segmenting the arthropod ancestor

    Molecular evidence for a single origin of ultrafiltration-based excretory organs

    Get PDF
    Under embargo until: 2021-06-23Excretion is an essential physiological process, carried out by all living organisms, regardless of their size or complexity.1, 2, 3 Both protostomes (e.g., flies and flatworms) and deuterostomes (e.g., humans and sea urchins) possess specialized excretory organs serving that purpose. Those organs exhibit an astonishing diversity, ranging from units composed of just few distinct cells (e.g., protonephridia) to complex structures, built by millions of cells of multiple types with divergent morphology and function (e.g., vertebrate kidneys).4,5 Although some molecular similarities between the development of kidneys of vertebrates and the regeneration of the protonephridia of flatworms have been reported,6,7 the molecular underpinnings of the development of excretory organs have never been systematically studied in a comparative context.4 Here, we show that a set of transcription factors (eya, six1/2, pou3, sall, lhx1/5, and osr) and structural proteins (nephrin, kirre, and zo1) is expressed in the excretory organs of a phoronid, brachiopod, annelid, onychophoran, priapulid, and hemichordate that represent major protostome lineages and non-vertebrate deuterostomes. We demonstrate that the molecular similarity observed in the vertebrate kidney and flatworm protonephridia6,7 is also seen in the developing excretory organs of those animals. Our results show that all types of ultrafiltration-based excretory organs are patterned by a conserved set of developmental genes, an observation that supports their homology. We propose that the last common ancestor of protostomes and deuterostomes already possessed an ultrafiltration-based organ that later gave rise to the vast diversity of extant excretory organs, including both proto- and metanephridia.acceptedVersio
    corecore