1,721,204 research outputs found
Cell to cell interactions in ovarian follicles of insects with different types of oogenesis
No full textVitellogenesis in the stick insect Bacillus rosssius (Rossi). Ultrastructural observations on ovarian follicle cells
No full textTHE FOLLICLE-OOCYTE INTERACTION IN OVARIAN FOLLICLES OF THE STICK ISNECT BACILLUS ROSSIUS (ROSSI):(INSECTA:PHASMATODEA)
No full textThe spermatozoon of Truncatella (s.str.) subcylindrica (L.) (Gastropoda Prosobranchia)
No full textThe spermiogenesis of Truncatella (s. str.) subcylindrica (L.) (Prosobranchia, Truncatellidae) has been studied with the electron microscope. The different parts of the spermatozoon are arranged in a normal sequence but they have nevertheless, certain peculiarities which deserve attention: The nucleus is almost entirely helical; two concentric rings of microtubules are contained within the walls of the acrosomal cone the inner one reaching only half way up the cone. The «coarse fibres» present in the terminal segment of the axoneme of other kinds of Prosobranchs are not present here. Through the study of the several phases of the spermiogenesis it has been ascertained that the acrosomal cone and the acrosomal rod derive from the Golgi complex and that the classical centriole disappears after the very first phases of the spermatid’s maturation
Vitellogenesis in the stick insect Bacillus rossius (Rossi). Ultrastructural observations on developing oocytes
No full textSulla fine struttura del microscopio negli Insetti. XVIII. L'uovo di Chamaemyia flavipalpis (Haliday) e di Parochthiphila coronata (Loew) (Diptera, Chamaemyiidae)
No full textReview of LOBI Research carried out at Ispra JRC
No full textThe analysis of experiments performed in LOBI-Mod2 test facility brought to the understanding and the characterization of selected phenomena occurring following Small Break Loss of Coolant (SBLOCA) occurrence. LOBI is an experimental simulator of Pressurized Water Reactors (PWR) managed by EURATOM. The concerned phenomena include natural circulation, loop seal clearing, dry-out occurrence and evolution, effect of thickness of downcomer in reactor pressure vessel simulator, and stratification in hot leg.
The present paper was prepared on the occasion of the EURATOM workshop organized by JRC Ispra at Ispra in 1986 (July 4)
Notulae Malacologicae XIV. I Molluschi delle Alpi Apuane. Elenco delle specie viventi con descrizione di una nuova specie: Vitrinobrachium baccettii n. sp.
Full text linkEGG CHORION ARCHITECTURE IN STICK INSECTS (PHASMATODEA)
No full textComparative analysis of egg chorion architecture by scanning and transmission electron microscopy is reported in about 50 species of stick insects (Phasmatodea). Particular attention has been paid to: (1) synthesis and structure of egg shell layers; (2) egg shape; (3) morphology of the external chorionic surface; (4) position and structure of the micropylar plate and its cup; (5) morphology and details of the operculum, including capitulum or pseudocapitulum; and (6) posterior pole differentiation (the so-called polar mound). The taxonomic value of the various characters is discussed: some are clearly species-specific, while others (such as general egg shape and micropylar plate) appear to reflect phylogenetic relationships of higher rank. Intraspecific features, such as the fine chorionic and opercular patterns of Bacillus and Clonopsis, have been recognized. In natural hybrids, egg chorion architectures were related to that of the parent species, resembling one of the parents in some cases and being intermediate between the 2. The study of the Phasmatodea egg can provide much taxonomic information that is useful in the definition of natural groups
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