Fucosylated chondroitin sulfate CD was isolated from the sea cucumber Cucumaria djakonovi collected from the Avachinsky Gulf of the eastern coast of Kamchatka. Structural characterization of CD was performed using a series of non-destructive NMR spectroscopic procedures. The polysaccharide was shown to contain a chondroitin core [→3)-β-d-GalNAc-(1→4)-β-d-GlcA-(1→]_n where about 60% of GlcA residues were 3-O-fucosylated, while another part of GlcA units did not contain any substituents. The presence of unsubstituted both at O-2 and O-3 glucuronic acid residues in a structure of holothurian chondroitin sulfate is unusual and has not been reported previously. Three different fucosyl branches Fucp2S4S, Fucp3S4S and Fucp4S were found in the ratio of 2:1:1. The GalNAc units were mono- or disulfated at positions 4 and 6. Anti-inflammatory activity of CD was assessed on a model of acute peritoneal inflammation in rats. About 45% inhibition was found for CD, while a structurally related linear chondroitin sulfate SS from cartilage of the fish Salmo salar demonstrated only 31% inhibition, indicating that the presence of sulfated fucosyl branches is essential for anti-inflammatory effect of chondroitin sulfates of marine origin.

Two fucosylated chondroitin sulfates were isolated from the sea cucumbers Psolus peronii and Holothuria nobilis using a conventional extraction procedure in the presence of papain, followed by anion-exchange chromatography on DEAE-Sephacel. Their composition was characterized in terms of quantitative monosaccharide and sulfate content, and structures were mainly elucidated using 1D- and 2D-NMR spectroscopy. As revealed by the data of the NMR spectra, both polysaccharides along with the usual fucosyl branches contained rare disaccharide branches α-D-GalNAc4S6R-(1→2)-α-L-Fuc3S4R → attached to O-3 of the GlcA of the backbone (R = H or SO₃⁻). The polysaccharides were studied as stimulators of hematopoiesis in vitro using mice bone marrow cells as the model. The studied polysaccharides were shown to be able to directly stimulate the proliferation of various progenitors of myelocytes and megakaryocytes as well as lymphocytes and mesenchymal cells in vitro. Therefore, the new fucosylated chondroitin sulfates can be regarded as prototype structures for the further design of GMP-compatible synthetic analogs for the development of new-generation hematopoiesis stimulators.

A new species, Psolidium kharlamenkoi n. sp. (Echinodermata: Dendrochirotida: Psolidae) is described from the Kuril Islands. The new species is distinguished from all previously described species of the genus Psolidium by combination of the external features, ossicles morphology and coloration.

A new species of dendrochirotid holothurian, Cucumaria fedotovi sp. nov. (Holothuroidea, Dendrochirotida, Cucumariidae), has been described in the Karaginskii Gulf, Bering Sea, Russia, from the depths of 31–34 m. The new species differs from the other species of the genus Cucumaria by the shape of ossicles of the body skin and by tube feets. The new species is characterized by ossicles in form of large lobed perforated plates with sharp teeth on the outer edge. In the tube feets, large, specific, laciniate, stellate plates predominate (up to ten rays), with numerous holes and sharp teeth along the outer edge.

Two new species of the genus Echinopsolus—E. sanamyanorum and E. onekotanensis are described. This genus is new for North-Western Pacific marine fauna. Echinopsolus sanamyanorum was collected in the Avacha Gulf (south-east coast of Kamchatka), E. onekotanensis—near the Onekotan Island (The Kuril Islands).

A comparative analysis of the brittle star fauna of the seas surrounding the Russian Federation (White, Barents, Kara, Laptev, East Siberian, Chukchi, Bering, and Black seas and the Sea of Okhotsk and the Sea of Japan) was carried out based on both published and original data. The number of brittle star species in the seas under consideration totals 99. The largest number of species is found in the Sea of Okhotsk (54 species), compared to the lowest number in the Black and White seas (four and five species, respectively). Three groups are naturally distinguished in the ophiuroid faunas of the study area: the fauna of the seas of the Arctic Ocean, the Far Eastern seas, and the Black Sea. In the group of fauna in the Arctic Ocean, the greatest similarity in species composition was noted between the Kara and Laptev seas; in the group of faunas in Far Eastern seas, it is between the Sea of Japan and the Sea of Okhotsk. The Bering and Chukchi seas showed the greatest similarity between these two groups. Autochthonous tendencies of fauna formation at the species level prevail in the Far Eastern seas of Russia, while allochthonous trends, to varying degrees, are observed in the other seas (introductions of species from neighboring seas with richer fauna).