Three-year-old birch (Betula pendula Roth.) seedlings were exposed, in the field, to supplemental levels of UV-B radiation. Control seedlings were exposed to ambient levels of UV radiation, using arrays of unenergized lamps. A control for UV-A radiation was also included in the experiment. Enhanced UV-B radiation had no significant effects on height growth, and shoot and root biomass of birch seedlings. Leaf expansion rate increased transiently in the middle of the growing period in enhanced UV-B-and UV-A-exposed plants; however, final leaf size and relative growth rate remained unaffected. Leaf thickness and spongy intercellular spaces were increased in UV-B-exposed seedlings along with increased density of glandular trichomes. At the ultrastructural level, enhanced UV-B increased the number of cytoplasmic lipid bodies, and abnormal membrane whorls were found. Both enhanced UV-B and UV-A radiation induced swelling of chloroplast thylakoids. Stomatal density and conductance were significantly increased by elevated UV-B radiation. UV-A radiation increased the length and width of stomata, whereas UV-B radiation had only a marginal effect on stomatal size. UV-A and enhanced UV-B radiation attenuated the appearance of necrotic spots in autumn, probably caused by the fungus Pyrenopeziza betulicola, suggesting a direct harmful effect of UV on pathogens or reduced susceptibility to pathogens in UV-exposed seedlings. Secondary metabolite analysis showed increases in (+)-catechin, quercetin, cinnamic acid derivative, apigenin and pentagalloylglucose in birch leaves under enhanced UV-B radiation. Negative correlations between apigenin, and particularly quercetin concentrations and lipid peroxidation levels indicated an antioxidant role of secondary metabolites in birch leaves exposed to UV-B radiation.
The peculiarities of the survival and adaptation of deep-sea organisms raise interest in the study of their metabolites as promising drugs. In this work, the hemolytic, cytotoxic, antimicrobial, and enzyme-inhibitory activities of tentacle extracts from five species of sea anemones (Cnidaria, orders Actiniaria and Corallimorpharia) collected near the Kuril and Commander Islands of the Far East of Russia were evaluated for the first time. The extracts of Liponema brevicorne and Actinostola callosa demonstrated maximal hemolytic activity, while high cytotoxic activity against murine splenocytes and Ehrlich carcinoma cells was found in the extract of Actinostola faeculenta. The extracts of Corallimorphus cf. pilatus demonstrated the greatest activity against Ehrlich carcinoma cells but were not toxic to mouse spleen cells. Sea anemones C. cf. pilatus and Stomphia coccinea are promising sources of antimicrobial and antifungal compounds, being active against Gram-positive bacteria Bacillus subtilis, Staphylococcus aureus, and yeast Candida albicans. Moreover, all sea anemones contain α-galactosidase inhibitors. Peptide mass fingerprinting of L. brevicorne and C. cf. pilatus extracts provided a wide range of peptides, predominantly with molecular masses of 4000–5900 Da, which may belong to a known or new structural class of toxins. The obtained data allow concluding that deep-sea anemones are a promising source of compounds for drug discovery.
A description of the intertidal biota of volcanic Yankich Island (Ushishir Islands, Kuril Islands) is given. The species composition and vertical distribution pattern of the intertidal communities at various localities are described in relation to environmental factors, such as nature of the substrate, surf conditions and volcanic vent water. The macrobenthos is poor in the areas directly influenced by high temperature (20-40°C) and high sulphur content. There are no marked changes in the intertidal communities in the areas of volcanic springs that are characterised by temperature below 10°C and by the absence of sulphur compounds. In general, the species composition and distribution of the intertidal biota are ordinary for the intertidal zone of the middle Kuril Islands. But there are departures from the typical zonation of the intertidal biota. Also, mass populations of Balanus crenatus appear.
Characteristics of vertical distribution, species composition and biogeographical structure of macrobenthos of the intertidal communities of Kunashir Island (South Kurile Islands) are described. In the rocky and bouldery intertidal zones, communities dominated by barnacle Chthamalus dalli and a gastropod species Littorina sitkana with the poor species composition of the macrobenthos are typical for the upper intertidal subzone. The middle intertidal subzone is occupied by fucoid assemblages. The dense beds of laminarian algae dominate in the lower intertidal subzone with the total macrobenthic biomass up to 100 kg wet wt m −2 . On wave-exposed sandy beaches formed by clean sand, populations of the macrobenthic organisms are very poor, and macrophytes and the other attached forms are absent. The communities dominated by eelgrass Zostera japonica and a gastropod species Batillaria cumingii are found only in the sandy intertidal zones of the southern coast of Kunashir Island, in Izmeny Bay. Reduction of species richness and increase of biomass of macrobenthos have been recorded from 1963 to 1991 in Izmeny Bay, and it is due to the fact that this area has been exposed to anthropogenic impact. At least, 563 species of macrobenthos are found in the intertidal zone of Kunashir Island. Pacific low-boreal and Pacific wide-boreal species are dominant. Warm-water species are more abundant in the intertidal zones of Izmeny Bay and on the Sea of Okhotsk coast as compared to those on the Pacific coast of Kunashir Island. It is probably associated with the flow patterns of the Soya Warm Current. Species composition and distribution of the intertidal macrobenthos of Kunashir Island are typical for the low-boreal intertidal zone with irregular diurnal and semi-diurnal tides. The intertidal zones of Kunashir Island and neighboring Shikotan Island have similar species composition and distribution patterns of the macrobenthic communities.
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