Vol 44, No 4 (2018)

This review is devoted to the analysis of publications on studies of phlorotannins, which are polyphenolic metabolites of brown algae. Their properties, the pathway of biosynthesis, and the structural diversity and classification of phlorotannins, as well as the methods for their isolation and determination of their metabolic profiles, are examined. The antioxidant, antitumor, and antimicrobial activities of phlorotannins and their role in the regulation of enzyme activity are discussed. These properties of phlorotannins determine the prospects of using phlorotannins in pharmacology.

The results of observations on the distribution of beluga whales, Delphinapterus leucas (Pallas, 1776), in three large rivers of western Kamchatka in the summer and autumn seasons are discussed. In the summer, the number of beluga whales in the Khairyuzova, Belogolovaya, and Moroshechnaya rivers reaches 111–250 individuals. Most of the belugas enter the rivers during the flood tidal phase: the number of animals in the estuaries increases along with the rising water level to the maximum value at spring tide. The belugas do not move upstream out of the estuaries and tend to remain in the zone of mixing riverine and marine waters, where 20 species of fish and three species of invertebrates have been identified. At ebb tide, the belugas leave for the sea; however, during a large run of salmon some individuals remain in the estuaries and continue hunting in deep-water areas. The main issue that causes beluga whales to form summer aggregations in Kamchatkan rivers is the hunt for salmon. The distribution of beluga whales in river estuaries is defined by the dynamics and intensity of salmon spawning runs. The preference of beluga whales for these rivers can be explained by the channel type of their estuaries.

The mandibles in the first zoeal stage of five species of the burrowing shrimp genera Upogebia (infraorder Gebiidea) and Nihonotrypaea (infraorder Axiidea) have been examined by scanning electron microscopy. The general shape of the mandibles in Upogebia zoeae is similar to that in Anomura larvae; in Nihonotrypaea, it is intermediate between the mandibles of anomuran and caridean shrimp larvae. The asymmetry of the mandibles, which is more pronounced in Nihonotrypaea, is confirmed. Species-specific features of the structure of the incisor process are found in three Upogebia species, while two Nihonotrypaea species almost do not differ in the mandible structure in their zoea I larvae. The morphological features of the mandibles indicate differences in the diet of Upogebia and Nihonotrypaea larvae. Under natural conditions, zoea I of the studied Nihonotrypaea species may feed on diatoms, which should be taken into account when rearing these decapod larvae in the laboratory.

The suggestion that the fish specimens caught in the littoral zone off Nedorazumeniya Island, Taui Bay, Sea of Okhotsk, belong to the eelpout species Magadanichthys skopetsi [23] and Hadropareia middendorffii Schmidt, 1904 has been confirmed by the analysis of their molecular-genetic and morphological characters. Their karyotypes have been studied for the first time: M. skopetsi, 2n = 48 (2 meta-, 26 subtelo-, and 20 acrocentric chromosomes), NF = 50; H. middendorffii, 2n = 48 (2 meta-, 36 subtelo-, and 10 acrocentric chromosomes), NF = 50. As a result of a comprehensive study, the levels of interspecific differentiation of these species has been established, the degree of intraspecific variability has been determined, and the lack of the population-geographical subdivision of H. middendorffii has been shown.

The long-term variations in blood biomarkers and weight–size characteristics of the round goby, Neogobius melanostomus (Pallas, 1814), have been studied in specimens collected from two sites of the southwestern Sea of Azov. The fish from catches of 2011–2012 showed a decrease in the size and weight parameters and an increase in the antioxidant enzyme activities and the level of oxidized serum proteins compared to the values in the fish caught in 2003. The ecological causes of the observed differences and the possibility of using the studied fish blood biomarkers in programs of monitoring the marine coastal waters are discussed.

The main components of the antioxidant (AO) system, that is, the activities of the antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase, as well as the glutathione content of cells of the digestive organs, have been measured in 26 species of marine invertebrates that belong to four taxonomic groups from the Possiet Bay, Sea of Japan. It has been shown that the activities of antioxidant enzymes and glutathione content are species specific. In the digestive organs of echinoderms, the activities of antioxidant enzymes and the glutathione content are generally higher compared with those in mollusks. All the studied species exhibit the greatest variability in the activities of catalase and glutathione peroxidase; the lowest variability occurred in activities of superoxide dismutase and glutathione content. The possible causes of the differences in the levels of the investigated components of the AO system are discussed.