Silica-containing inclusions in the cytoplasm of diatom Synedra acus.

Cells of the araphid pennate diatom Synedra acus subsp. radians contain large inclusion (1-15 µm) storing silica, as revealed by transmission electron microscopy and EDX-analysis. The size of the inclusions increases with the time of cultivation of diatoms. Approximate concentration of SiO2 in the inclusions is 1-4%. It is assumed that silica in the inclusions is present as gelatinized silica-gel. These results explain the possible mechanism of transport of silicic acid into the cell against the concentration gradient.

Identifying N-terminal peptides by a combination of the edman procedures with a bromine isotope tag: Application to the silicateins.

Silicateins are proteins found within spicules of siliceous sponges. They are analogs of proteinases cathepsins; they catalyze the transformation of silicic acid esters into biogenic silica (SiO2 ·nH2 O), and are believed to take part in the processes of silicification in marine and freshwater sponges. Earlier studies by Kalyuzhnaya et al. revealed that the Baikal Sponge Lubomirskia baicalensis Pallas, 1773 (L. baicalensis) contains a gene 1988 bp long, which hosts four sequences that encode four mRNAs giving rise to silicateins α1, α2, α3 and α4 (SILα1, SILα2, SILα3, SILα4) whose predicted amino acid sequences are similar to those of the predicted sequences of marine sponge silicateins. However, the sequences of mature silicateins of L. baicalensis remained unknown, since their N-terminal peptides were not identified. We found the sequences of these N-terminal peptides using a combination of the Edman procedure, which involved reaction with phenylisothiocyanate, treatment with trifluoroacetic acid and trypsinolysis followed by treatment with 4-bromine-phenylisothiocyanate performed directly within polyacrylamide gel bands, and subsequent mass spectrometry. The N-terminal peptides are YAESIDWR (SILα1), YVDSIDWR (SILα2 and α4), and YADSLDWR (SILα3). All mature silicateins of L. baicalensis had a length 217 amino acid residues.

The effect of bloom of filamentous green algae on the reproduction of yellowfin sculpin Cottocomephorus grewingkii (Dybowski, 1874) (Cottoidae) during ecological crisis in Lake Baikal.

In shallow water areas of open Lake Baikal, filamentous green alga of the genus Spirogyra grows abundantly. Together with alga of the genus Ulothrix, it forms algal mats. According to our observations from 2010 to 2013, the spawning habitat conditions for the yellowfin sculpin Cottocomephorus grewingkii (Dybowski, 1874) (Cottidae) proved to be significantly disturbed in the littoral zone of Listvennichnyi Bay (southern Baikal), which, in turn, reduced the number of egg layings. With a 100% projective cover of the floor and a high density of green filamentous algae, the shallow-water stony substrate becomes completely inaccessible for spawning of the August population.

Unique configuration of genes of silicon transporter in the freshwater pennate diatom Synedra acus subsp. radians.

The existence of the cluster of duplicated sit silicon transporter genes in the chromosome of the diatom Synedra acus subsp. radians was shown for the first time. Earlier, the localization of sit genes in the same chromosome and cluster formation caused by gene duplication was shown only for the marine raphid pennate diatom P. tricornutum. Only non-clustered sit genes were found in the genomes of other diatoms. It is reasonable to assume that sit tandem (sit-td) and sit triplet (sit-tri) genes of S. acus subsp. radians occurred as a result of gene duplication followed by divergence of gene copies.

[RADIATION SAFETY DURING REMEDIATION OF THE "SEVRAO" FACILITIES].

Within a framework of national program on elimination of nuclear legacy, State Corporation "Rosatom" is working on rehabilitation at the temporary waste storage facility at Andreeva Bay (Northwest Center for radioactive waste "SEVRAO"--the branch of "RosRAO"), located in the North-West of Russia. In the article there is presented an analysis of the current state of supervision for radiation safety of personnel and population in the context of readiness of the regulator to the implementation of an effective oversight of radiation safety in the process of radiation-hazardous work. Presented in the article results of radiation-hygienic monitoring are an informative indicator of the effectiveness of realized rehabilitation measures and characterize the radiation environment in the surveillance zone as a normal, without the tendency to its deterioration.

Radiation safety during remediation of the SevRAO facilities: 10 years of regulatory experience.

In compliance with the fundamentals of the government's policy in the field of nuclear and radiation safety approved by the President of the Russian Federation, Russia has developed a national program for decommissioning of its nuclear legacy. Under this program, the State Atomic Energy Corporation 'Rosatom' is carrying out remediation of a Site for Temporary Storage of spent nuclear fuel (SNF) and radioactive waste (RW) at Andreeva Bay located in Northwest Russia. The short term plan includes implementation of the most critical stage of remediation, which involves the recovery of SNF from what have historically been poorly maintained storage facilities. SNF and RW are stored in non-standard conditions in tanks designed in some cases for other purposes. It is planned to transport recovered SNF to PA 'Mayak' in the southern Urals. This article analyses the current state of the radiation safety supervision of workers and the public in terms of the regulatory preparedness to implement effective supervision of radiation safety during radiation-hazardous operations. It presents the results of long-term radiation monitoring, which serve as informative indicators of the effectiveness of the site remediation and describes the evolving radiation situation. The state of radiation protection and health care service support for emergency preparedness is characterized by the need to further study the issues of the regulator-operator interactions to prevent and mitigate consequences of a radiological accident at the facility. Having in mind the continuing intensification of practical management activities related to SNF and RW in the whole of northwest Russia, it is reasonable to coordinate the activities of the supervision bodies within a strategic master plan. Arrangements for this master plan are discussed, including a proposed programme of actions to enhance the regulatory supervision in order to support accelerated mitigation of threats related to the nuclear legacy in the area.

Sequencing of the complete genome of an araphid pennate diatom Synedra acus subsp. radians from Lake Baikal.

High-throughput method of sequencing was applied to determine the complete nucleotide sequence of an araphid pennate diatom Synedra acus subsp. radians from Lake Baikal (East Siberia). The assembled genome has a total length of 98 Mbp, the mean coverage is 33x. Structure-functional annotation of the genome was performed.

Similarity of structure of taxonomic bacterial communities in the photic layer of Lake Baikal's three basins differing in spring phytoplankton composition and abundance.

Pyrosequencing of amplicons V3-V4 of the 16S rRNA gene of 30 samples from the photic layer across the three basins of Lake Baikal has revealed 44 958 sequences of the domain Bacteria. The most representative phylums among all classified sequences in the samples were Actinobacteria, Bacteroidetes, Verrucomicrobia, Proteobacteria, Acidobacteria, and Cyanobacteria. As much as 38.5% of the total number of sequences has been determined to the level of genus. The taxonomic composition of bacterial communities was similar regardless of some differences in the composition and abundance of spring phytoplankton. Closely related or identical sequences of bacteria inhabiting the epilimnion of other lakes worldwide have been discovered for most sequences. This confirms the similarity of microbial communities in freshwater ecosystems.

[Health-care provision to the rescue and other emergency operations in case of radiation accidents at facilities under FMBA of Russia service].

The article deals with the main tasks of health-care provision to the rescue and other emergency operations (ROEO) and organization of medical evacuation system FMBA of Russia in case of radiation accidents. The risk (threat) for workers engaged in ROEO, depending on the level of exposure of the radiation factor, is analyzed and recommendations for protective measures are considered. The authors showed the important role of the practical skills and knowledge of staff of institutions of FMBA of Russia and emergency response teams of radiation-hazardous facilities for address issues of healthcare provision to ROEO.

Biological activity of some derivatives of ß-cyclodextrin.

New compounds of ß-cyclodextrin containing covalently bound (conjugated) residues of acetylsalicylic and 1-(4-isobutylphenyl)-propionic acids were synthesized in the reaction of chlorides of the corresponding acids with ß-cyclodextrin. We studied antiplatelet and antiphlogistic properties of these substances. It was shown that new compounds are comparable and in some cases are superior to the reference drugs acetylsalicylic acid and ibuprofen by anti-inflammatory and antiaggregant activities.

Novel fluorescent dyes based on oligopropylamines for the in vivo staining of eukaryotic unicellular algae.

Weakly basic fluorescent dyes are used to visualize organelles within live cells due to their affinity to acidic subcellular organelles. In particular, they are used to stain the silica deposited in the silica deposition vesicles (SDVs) of diatoms during the course of their frustule synthesis. This study involved the synthesis of fluorescent dyes derived from oligopropylamines, compounds similar to those found in diatoms. The dyes were obtained by reacting oligopropylamines with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole. The reaction was realized using methylated oligopropylamines with two or three nitrogen atoms and yielded two novel fluorescent dyes: NBD-N2 and NBD-N3. The dyes appeared to be highly efficient in the in vivo staining of growing siliceous frustules of diatoms at concentrations at least 10 times lower than those required for staining with HCK-123. NBD-N3 also efficiently stained other subcellular vesicles of eukaryotic unicellular algae. NBD-N2 stained only growing diatom frustules, whereas NBD-N3 also stained various subcellular organelles of different eukaryotic unicellular algae. NBD-N2 and NBD-N3 were not removed from stained diatom frustules by drastic treatments with H(2)SO(4) and H(2)O(2). Fluorescent silica can also be obtained by its chemical precipitation in the presence of NBD-N2 and NBD-N3.

Medical and radiological aspects of emergency preparedness and response at SevRAO facilities.

Regulatory cooperation between the Norwegian Radiation Protection Authority and the Federal Medical Biological Agency (FMBA) of the Russian Federation has the overall goal of promoting improvements in radiation protection in Northwest Russia. One of the projects in this programme has the objectives to review and improve the existing medical emergency preparedness capabilities at the sites for temporary storage of spent nuclear fuel and radioactive waste. These are operated by SevRAO at Andreeva Bay and in Gremikha village on the Kola Peninsula. The work is also intended to provide a better basis for regulation of emergency response and medical emergency preparedness at similar facilities elsewhere in Russia. The purpose of this paper is to present the main results of that project, implemented by the Burnasyan Federal Medical Biophysical Centre. The first task was an analysis of the regulatory requirements and the current state of preparedness for medical emergency response at the SevRAO facilities. Although Russian regulatory documents are mostly consistent with international recommendations, some distinctions lead to numerical differences in operational intervention criteria under otherwise similar conditions. Radiological threats relating to possible accidents, and related gaps in the regulation of SevRAO facilities, were also identified. As part of the project, a special exercise on emergency medical response on-site at Andreeva Bay was prepared and carried out, and recommendations were proposed after the exercise. Following fruitful dialogue among regulators, designers and operators, special regulatory guidance has been issued by FMBA to account for the specific and unusual features of the SevRAO facilities. Detailed sections relate to the prevention of accidents, and emergency preparedness and response, supplementing the basic Russian regulatory requirements. Overall it is concluded that (a) the provision of medical and sanitary components of emergency response at SevRAO facilities is a priority task within the general system of emergency preparedness; (b) there is an effective and improving interaction between SevRAO and the local medical institutions of FMBA and other territorial medical units; (c) the infrastructure of emergency response at SevRAO facilities has been created and operates within the framework of Russian legal and normative requirements. Further proposals have been made aimed at increasing the effectiveness of the available system of emergency preparedness and response, and to promote interagency cooperation.

[Ultrastructure of diatom Synedra acus subsp. radians as revealed by transmission electron microscopy after mild silica dissolution].

A diatom Synedra acus subsp. radians (Kütz.) Skabitsch. has been studied by transmission electron microscopy. Examination of ultrathin sections demonstrated that silica dissolution in ammonium fluoride pH 5 under mild conditions leaves the key ultrastructural elements intact. The ultrastructure and arrangement of the cell organelles was studied during ontogeny. Silicalemma-surrounded silica deposition vesicles (SDVs) with maturating daughter valves and forming girdle bands have been identified. This method of SDV visualization offers considerable advantages over the standard approach without silica dissolution.

[A new bromine-containing reagent for cysteine modification].

5-Bromo-2[(2-iodoacetyl)amino]benzenesulfonic acid (AIBSA), a reagent for modification of free of cysteine thiol groups in proteins and peptides, was synthesized. Rate constants of its interaction with thiol groups were determined. The presence of a bromine atom allows an easy identification of the AIBSA-labeled peptides in mass spectra due to the characteristic isotope distribution. The compound is stable in solution and under exposure to light.

Aberration of morphogenesis of siliceous frustule elements of the diatom Synedra acus in the presence of germanic acid.

Addition of germanic acid into the culture medium of the diatom Synedra acus subsp. radians (Kutz.) Skabitsch. had nearly no influence on the culture growth at the Ge/Si molar ratio 0.01, but stopped it at ratios 0.05 and higher. It was shown by mass-spectrometry that at the Ge/Si ratio 0.01 germanium was incorporated in both the cytoplasm and siliceous valves, whereas at Ge/Si 0.05 it was incorporated into the cytoplasm but almost failed to accumulate in the valves. At Ge/Si 0.1 germanium was accumulated in the cytoplasm, but its incorporation into the valves terminated. Studies on the cell morphology by light, epifluorescence, and transmission electron microscopy showed that high concentrations of germanic acid induced disorders in morphogenesis of the siliceous frustule and accumulation of large rhodamine-stainable electron-dense inclusions. Model chemical experiments with over-saturated solutions of silicic acid in the presence of polyallylamine revealed that addition of 5% germanic acid considerably accelerated coagulation of silica. Hence, the toxic effect of germanic acid on diatoms could be caused by changes in coagulation of silica.