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vasa (vas)-related genes are members of the DEAD-box protein family and are expressed in the germ cells of many Metazoa. We cloned vasa-related genes (PpVLG, CpVLG) and other DEAD-box family related genes (PpDRH1, PpDRH2, CpDRH, AtDRHr) from the colonial parasitic rhizocephalan barnacle Polyascus polygenea, the non-colonial Clistosaccus paguri (Crustacea:(More)
Commercial crab populations off the Kamchatka coasts are infested to a considerable degree by the rhizocephalan parasite Briarosaccus callosus: of 769 Lithodes aequispina males examined, 43 (5.7%) were parasitized. Infestations result in the feminization of the crabs, a significant decrease in the cheliped length, and a significant decrease in the carapace(More)
Topological patterns in the development and evolution of metazoa, from sponges to chordates, are considered by means of previously elaborated methodology, with the genus of the surface used as a topological invariant. By this means metazoan morphogenesis may be represented as topological modification(s) of the epithelial surfaces of an animal body. The(More)
Histological, cytochemical and ultrastructure research on the budding of the colonial ascidian Botryllus tuberatus aimed at searching for stem cells was performed. A dense mass of undifferentiated cells and the connection of the outer epidermal and inner atrial epithelia were revealed for the first time in the early buds of B. tuberatus. Undifferentiated(More)
The morphology of archaeocytes, sponge stem cells, was studied in Oscarella malakhovi during asexual reproduction (budding) using light and electron microscopy. Electron-dense germinal granules, which are ultrastructural markers and key organelles of metazoan germline cells and potentially gametogenic stem cells of asexually reproducing invertebrates, were(More)
Data are presented about the invasion level of commercially important crabs in the Sea of Okhotsk by rhizocephalan barnacles. Some general information concerning the structure, life cycle, and reproductive strategy of the parasitizing rhizocephalans and the effect on the Decapoda host. Practical recommendations have been proposed to decrease the infestation(More)
Literature data on the structure and origin of material of the germ cell line determinants and on the presence of products of nuclear and mitochondrial genomes in the structured germ determinants (nuage) are reviewed. The personal data, obtained on spermatogenic cells of sea urchin and of other marine invertebrates, evidence the transformation of the(More)
Biological systems are considered that are capable of dynamic self-organization, i.e., spontaneous emergence of spatio-temporal order with the formation of various spatio-temporal patterns. A cell is involved in the organization of ontogenesis of all stages. Embryonic cells exhibit coordinated social behavior and generate ordered morphological patterns(More)
The review presents a topological interpretation of some morphogenetic events through the use of well-known mathematical concepts and theorems. Spatial organization of the biological fields is analyzable in topological terms. Topological singularities inevitably emerging in biological morphogenesis are retained and transformed during pattern formation. It(More)
The specific features of the reproductive stage of the life cycle have been studied in the rhizocephalan barnacle Polyascus polygenea, a parasite of the coastal crab Hemigrapsus sanguineus. It is shown that a single crab can bear 1 to 8 externae of P. polygenea. The fecundity of the parasite depends on the size of the externae and their number on the host(More)