Vol 43, No 5 (2017)

The structure and mechanism of the biological activity of diarrhetic shellfish toxins (DSTs) is presented; a short description of identification and quantitative analysis is given as well as information on DSTproducing organisms. The problem of diarrhetic poisoning by shellfish that inhabit the Russian seas is considered. The legal aspects of safety regulation and monitoring of okadaic acid group toxins in food products in different countries are discussed.

Eleven specimens of leptostracans were collected with the help of the camera-epibenthic sledge (C-EBS) in August 2015 at depth 3287–4469 m in the Kurile depression of the Sea of Okhotsk and in the Pacific Ocean to the east of the Boussole Strait (Kurile Islands) during the Russian-German expedition Sokho-Bio. All these specimens relate to new species of genera Nebaliella Thiele, 1904 from family Nebaliidae: N. ochotica. Nebaliella ochotica sp. nov. varies from the other species of Nebaliella by the unique values of the ratio of the rostral flange to exposed keel (2 : 1 in N. ochotica, 3 : 1 in N. antarctica, and 1 : 1 in other species). In this species, article 2 of mandible palp has 1 long seta by distodorsal corner, without stout spicular process and small setae; exopod of pleopod 1 has 5 stout long spicular setae on lateral border, with 1–2 stout long spicular setae on terminal border and with 1–3 distal spicular setae and 10–17 simple setae on medial border. Moreover, N. ochotica differentiates from N. brevicarinata, N. extrema and N. kurila by the absence of carina on anterolateral lower corner of carapace, arom N. brevicarinata and N. extrema—by the absence of ventroproximal tuberculate process on rostrum, and from N. antarctica and N. kurila—by compound articles 1 and 2 on peduncle of antenna.

The dynamics of the survival and number of female northern fur seals, Callorhinus ursinus, on Tyuleniy Island have been studied. The data on the age structure and physiological condition of females (obtained during observations in 1958–1988) were used to estimate the model parameters. The adequacy of the model estimates of female number was evaluated using the data on the number of newborn pups at the rookery in 1958–2013. It has been found that a reduction in the survival rate of individuals of younger age groups, a decrease in the proportion of females, as well as aging of the population occurred in the 1958–1988 period. The use of numerical simulation methods shows that the rate of survival of females among individuals under 3 years of age increased substantially after 1988, indicating a positive trend in the dynamics of their number.

The biomass of the walleye pollock (Theragra chalcogramma) stock in waters of Primorskii krai, Sea of Japan, during the 1976–2015 observation period ranged from 48000 to 373000 tons; their number ranged from 99 to 1115 million fish. Four very strong year-classes born in 1975, 1981, 1997, and 2006 have been identified. It has been shown that the duration of the sexual-maturity period is determined by the periodicity of the dynamics of the year-class strength close to the 9-year cycle. According to the results of numerical modeling, an increase in the walleye pollock stock in Primorye is expected from 2017 to 2020.

The influence of hypoxia on the morphological characteristics of circulating erythrocytes of the scorpion fish Scorpaena porcus (Linnaeus, 1758) has been investigated in an in vivo experiment. Under a 4-h adaptation of the fish to the conditions of ranked hypoxia their erythrocytes demonstrated a number of consecutive reactions. The volume and the surface area of the red blood cells was reduced by 4–5% (p < 0.001) at an oxygen concentration of 2.6 mg/L (30% saturation of water with oxygen) and increased by 4% (p < 0.001) at a concentration of 1.3 mg/L (15% saturation), relative to the control values (normoxia: 7–8 mg/L). The observed reaction of erythrocytes coincided quantitatively and qualitatively (the order of events) with the results of the experiments we performed previously in vitro. Our study has shown that the physiology of the black scorpion fish is tolerant to hypoxia and allows autonomous functioning of red blood cells under conditions of oxygen deficit.

An illustrated key for the identification of the first zoeal stage of burrowing shrimp of the infraorders Gebiidea and Axiidea in the plankton of Peter the Great Bay (the Sea of Japan) has been created. A summary of the main morphological features of gebiidean and axiidean larvae is presented. The possibility of variation of the number of zoeal stages in shrimp of the infraorders Gebiidea and Axiidea in different populations and/or under different laboratory conditions is discussed.

The taxonomic composition of bacteria associated with two species of tetrodotoxin-bearing (TTX-bearing) (Hubrechtella juliae and Lineus alborostratus) and two species of non-TTX-bearing (Quasitetrastemma stimpsoni and Malacobdella grossa) ribbon worms collected from the Peter the Great Bay of Sea of Japan was studied. Bacterial isolates were identified using 16S rRNA gene sequencing and phenotypic characteristics. Thirty-eight strains of heterotrophic bacteria from the eight genera: Pseudoalteromonas, Shewanella, Ruegeria, Pseudomonas, Defluviicoccus, Vibrio, Alteromonas, and Bacillus, were isolated and characterized. γ-Proteobacteria dominated among the associated microflora of nemerteans (76.3% of the total number of isolates). Sensitivity analysis of 38 strains to antibiotics of various classes revealed multiple resistance to three or more antibiotics in all of the studied isolates. The 15 bacterial strains isolated in the study exhibited antimicrobial activities against at least one of five indicator microorganisms, most of which corresponded to the Pseudoalteromonas genus. Screening of the TTX-producing bacteria was performed using confocal laserscanning microscopy and polyclonal antibodies. A TTX-producing strain, Pseudoalteromonas sp., was found in the nemertean H. juliae. A correlation between the presence of TTX-positive microflora and the toxicity of nemerteans was determined.

The mycobiota of bottom sediments at depths of 128−472 m was investigated in Barents and Kara sea areas remote from the shore. The species composition and fungal abundance, that is, the number of fungal colony-forming units (CFUs), were determined in 5 samples from the Kara Sea and in 14 samples of the Barents Sea. For the first time for the Arctic seas, the fungal biomass was determined in 12 samples of the bottom sediments from the Barents Sea. It was found that fungal abundance in the bottom sediments of the both seas did not exceed 13 CFUs per 1 g of dry substrate weight. In total, only 58 colonies of filamentous fungi belonging to 22 morphotypes, 8 of which were sterile, were isolated from all the samples. No more than six morphotypes were contained in 1 g of dried substrate; they were mostly species of the genus Cladosporium and sterile isolates. The study of the fungal biomass detected both spores and fungal mycelium in the bottom sediments. The total biomass was extremely low and ranged from 0.1 to 0.620 mg/g of the studied substrate. Small spores (with a diameter less than 3 μm) absolutely predominated (from 88 to 99.7% of the biomass).

The range of variation in the key components of enzymatic and low-molecular-weight antioxidant systems (AOSs) is determined for 17 dominant species of macroalgae from the Sea of Japan waters that are exposed to minimal anthropogenic pressure, during the period of their active vegetative growth. The maximum activity of superoxide dismutase, glutathione reductase, ascorbate peroxidase, and the highest content of glutathione and carotenoids are observed in members of the phylum Chlorophyta. The studied algae display a wide phenotypic variability in terms of catalase activity and ascorbate abundance in their tissues. Differences between species in the constitutive capacity of AOS are found within the systematic phyla. It is shown for the first time that warm-water algae of temperate latitudes have a lower content of low-molecular-weight antioxidants and a higher activity of key antioxidant enzymes compared to those recorded for cold-temperate species.