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Morphology, chemical composition and electrical properties of long monoaxonic spicules of the deep-sea hexactinellid sponge Hyalonema sieboldi were studied. In this paper we show for the first time that the spicules have an electrical resistance and can produce the piezoelectric effect. The piezoelectric properties of the organosilicon spicules seem to result from their complex multilayered organization. Mechanical tension can be detected between these layers in different parts of the spicules that disappears following the destruction of a spicule. Our findings on the presence of the piezoelectric effect in composite organosilicon material of the hexactinellid spicules may contribute to the creation of biomimetic materials capable of generating light emission. [ABSTRACT FROM AUTHOR]

The paper presents an original approach to the synthesis of polycalciumorganyl silsesquioxanes through the reaction of polyorganyl silsesquioxanes [RSiO1.5]n (where R is an ethyl and phenyl radical) with sea urchin skeleton under the conditions of mechanochemical activation. The novelty and practical significance of the present study lies in the use of an available natural raw source as a source of calcium ions to initiate the reaction of calcium silicate formation and create a matrix for the formation of a porous inorganic composite framework. The thermal stability of the introduced silicates, i.e., the ability to maintain a porous structure at high temperatures, is key to the production of an ordered porous material. The reaction scheme was proposed to be based on the interaction of calcium carbonate with the siloxane bond. FTIR, XRD, GPC, and TGA were used to study the composition and structure of the obtained materials. The cross-sectional area of the polymer chain and the volumes of the coherent scattering regions of the polymers obtained were calculated from the XRD data. To prepare the composites, the sea urchin skeleton was further modified with polycalciumorganyl silsesquioxanes in a toluene solution. To remove the sea urchin skeleton, the obtained biomimetic composites were treated with hydrochloric acid. The results of the morphological and surface composition studies are reported. The method proposed in the paper could be of fundamental importance for the possibility of obtaining structured porous composite materials for a wide range of practical applications, including for the purpose of creating a composite that may be a promising carrier for targeted delivery of chemotherapy agents. [ABSTRACT FROM AUTHOR]

The morphology, chemical composition, and optical properties of long monoaxonic spicules were studied in several species of marine deep-sea hexactinellid sponges of different orders and families: Asconema setubalense (Hexasterophora, Lyssacinosida) and Monorhaphis chuni Schulze (Monorhaphiidae). Their macrostructural organization is a system of thin layers laid around the central cylinder containing a square canal filled with organic matter. A significant role in spicule organization is played by the organic matrix. The macrostructural of organization of the spicule in Monorhaphis chuni is a system of the "cylinder-within-a-cylinder" type. However the spicule surface is covered with ridges. They penetrate a few layers into the spicule. Analysis of the elemental composition of the basalia spicule of Monorhaphis chuni demonstrates a heterogeneous allocation of C, O, Si on the spicule surface, subsurface layers, and on ridges. All studied spicules have the properties of anisotropic crystals and they demonstrate a capability to the birefrigence. On the other hand we discovered unique property of spicules--their capacity for triboluminescence. The discovery of triboluminescence in composite organosilicon materials of which the spicules of hexactinellid sponges are built may contribute to the creation of biomimetic materials capable of generating light emission. [ABSTRACT FROM AUTHOR]

Internal gonad morphology was examined in two species of elpidiid holothurians, Elpidia heckeri and Kolga hyalina, commonly occurring in the Central Arctic Ocean. The holothurians were sampled in August – September 2012 and in August 2018, at several locations in the Nansen and Amundsen Basins, in areas under the constant ice cover and in areas free of ice. Both species were observed at different reproductive stages and both are presumed to reproduce periodically. In 2012, spawning occurred at the beginning of September in Elpidia heckeri and from late August to early September in Kolga hyalina. There are reasons to believe that gametogenesis in K. hyalina depends on the availability of freshly deposited phytodetritus. The maximum oocyte size in Kolga hyalina (240 μm) was smaller than in Elpidia heckeri (390 μm). [ABSTRACT FROM AUTHOR]