Vol 45, No 2 (2019)

We present the first study on the quantity and diversity of the mycobiota in bottom sediments of the Chukchi Sea. During implementation of the RUSALCA-2012 program, 22 samples of bottom sediments from depths of 44–110 m were collected in late August–early September 2012. Fungi were isolated on agarized media (salinity 35 psu, temperature 6°C). Species identification was performed by morphological-cultural and molecular-genetic methods based on the nucleotide sequences of ITS1-ITS2 rDNA. A total of 128 colonies of mycelial fungi were isolated; 0 to 22 propagules were obtained from each 1 cm³ sample. The overall diversity was represented by 48 morphotypes belonging to 32 genera in 15 orders of ascomycetes and basidiomycetes. Ascomycetes predominated both in number and diversity. A number of species were found in marine ecosystems for the first time. The taxonomic position of nonsporulating isolates (13% of the total) was established using molecular techniques. Among them, high diversity was observed in the orders Pleosporales and Helotiales (Ascomycota).

In this study, induction of polyploidy by colchicine was investigated in Dunaliella salina. To induce polyploidy in the cells, different concentrations of colchicine (0.05, 0.1, 0.5 and 1%) were used in three periods of times 12, 24, and 36 h. Measurement of DNA content was done by Nano drop method. All concentrations of colchicine caused an increase in DNA content. Results showed that the highest value of DNA obtained related to algal cells were exposed to 1.0 and 0.5% colchicine for 36 h (0.213 μg/μL and 0.274 μg/μL, respectively), with respect to DNA content in control sample, these treatments caused induction of polyploidy in algal cells. Survival percentage of cells at all concentrations of colchicine significantly decreased. Based on obtained results from survival rate and DNA content, two concentrations of 0.1 and 0.5% colchicine were selected for other analysis. Colchicine treatments (0.1 and 0.5%) caused an increase in doubling time and specific growth rate declined in the treated algae. Pictures obtained by fluorescence microscopy and image analysis revealed a significant enhancement of the cell and nuclear size of the microalgae. Results of flow cytometry analysis indicated that percentage of polyploid cells in cultures treated by 0.1% colchicine was 58.26% and by 0.5% colchicine was 74.19%.

Accumulation of heavy metals and their effect on the composition of fatty acids and molecular species of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) has been studied in the molluskan organs and tissues of the Gray mussel from clean and polluted water areas of Peter the Great Bay of the Sea of Japan. The total load of heavy metals accumulated in the mussel was evaluated with the coefficient of total concentration (ΣCC), which turned out to be extremely high for all the organs studied in mollusks from a polluted site. Cu and Pb accounted for the main share in the total load. It was found that accumulation of heavy metals in the kidneys, gills, and muscles had no effect on the composition of fatty acids, molecular species, and forms of basic membrane lipids of PC and PE. It has been shown that high resistance of membrane lipids of the Gray mussel to chronic anthropogenic pollution with heavy metals allows the mussel to function under conditions of contamination.

In this article, we determined and described the complete mitochondrial genome of Terapon jarbua, which is 16 664 bp in length, containing 13 protein-coding genes, two rRNA genes, 22 tRNA genes, one origin of replication on the light-strand (O_L), and a putative control region (CR). The gene order and the base composition of T. jarbua mitogenome are similar to that of most other vertebrates. The overall base composition is 27.5% A, 26.0% T, 29.9% C, 16.6% G, respectively, with a slight AT bias (53.5%). All the protein-coding genes use the initiation codon ATG except COI use GTG. Most of them have TAA or TAG as the stop codon, except COII and ND4 use AGA, COIII and Cyt b use an incomplete stop codon TA and T, respectively. In order to further explore the structure of CR in Centrarchiformes, eight CR sequences from representative species were compared. Like that of other teleosts, the CR of the Centrarchiformes is also partitioned into three domains, including the termination associated sequence (TAS), the central conserved sequence blocks (CSB-E, D, B and A), and the conserved sequence blocks (CSB-2 and 3). We hope these results will provide consensus sequences of the conserved units of the CR in Centrarchiformes genomes, as well as useful molecular information for phylogenetic studies of Centrarchiformes.

The levels of Zn, Cu, Fe, Cd, and Pb were measured in thalli of the common brown algae species Scytosiphon lomentaria, Fucus evanescens, Stephanocystis crassipes, Silvetia babingtonii, and Saccharina japonica from Rudnaya Bay and adjacent waters. These data allowed assessment of the current spatial distribution of these elements over the waters of the study region and the species-specificity of algae as indicators of heavy metal pollution of the environment. It has been established that the main source of heavy metals entering the bay waters is the small harbor in its southern part, where lead and zinc concentrates from the Dalnegorsk Mining and Processing Plant are loaded on vessels for further transportation. The estimated trace-element composition of algae was compared to that of the samples collected in 2009, which is the year of the last increase and, simultaneously, completion of the production activity of the local lead smelting plant. The results show that by 2016 the concentration of Pb in S. lomentaria collected near Cape Briner at the entrance to the bay decreased 7.4 times. The reduction in the Zn content of S. lomentaria was not as impressive: from 2009 to 2016, it decreased 1.7 times. In algae from Lidovka Bay, which is located north of Rudnaya Bay, the Zn concentration in 2016 increased 1.67 times compared to that in 2010, which is obviously explained by the growing recreational pressure on the coast of this bay.