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Simplified dynamic models have been developed for predicting the concentrations of radiocesium, radiostrontium, and I in surface waters and freshwater fish following a large-scale radioactive fallout. The models are intended to give averaged estimates for radionuclides in water bodies and in fish for all times after a radioactive fallout event. The models are parameterized using empirical data collected for many lakes and rivers in Belarus, Russia, Ukraine, UK, Finland, Italy, The Netherlands, and Germany. These measurements span a long time period after fallout from atmospheric nuclear weapons testing and following the Chernobyl accident. The models thus developed were tested against independent measurements from the Kiev Reservoir and Chernobyl Cooling Pond (Ukraine) and the Sozh River (Belarus) after the Chernobyl accident, from Lake Uruskul (Russia), following the Kyshtym accident in 1957, and from Haweswater Reservoir (UK), following atmospheric nuclear weapons testing. The AQUASCOPE models (implemented in EXCEL spreadsheets) and model documentation are available free of charge from the corresponding author.

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Existing methods of predicting of radiocaesium transfer from soil to plants was critcally reviewed. The analysis of radiocaesium behavior in the system "soil solid phase/pore solution/plant" was carried out. Equations for calculation of radiocaesium uptake by plants as a function of soil properties were obtained and tested using the reported experimental data. Key soil parameters which natural variability and estimation difficulty are the main sources of prediction uncertainty were identified.

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A model of 137Cs vertical soil transport by a tree root system is presented. As distinct from other models the radionuclide root uptake is described as a reversible process and depth distribution of roots is given as a function of time. The model was used for prediction of 137Cs release from a surface disposal site located in a territory with conditions similar to that in the Chernobyl NPP exclusion zone. Prediction indicates that during several decades 137Cs transport from the waste layer by the root system of pine can lead to significant contamination of the soil surface due to needles fallout and, probably, ionic leakage from roots.

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Collapse of interlayer spaces of soil clay minerals can by caused by ammonium cation in concentrations as low as 10(-3) mol/l. The collapse leads to substantial decrease in the soil ability to fix 137Cs. This effect is reversible and the soil fixation ability recovers after the ammonium concentration decrease.

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During the years after the Chernobyl accident the radioceasium activity concentration in most contaminated aquatic ecosystems decreased markedly. Lakes with no permanent inflows and outflows (closed lakes), however, still present a radioecological problem which is expected to continue for some time. In this paper, a mechanistic model for the long-term prediction of radiocaesium behaviour in closed lakes is developed. The model of Prokhorov (Radiokhimiya (Radiochemistry) 11 (1969) 317) was modified to describe the effects of bottom sediment bioturbation, surface runoff from the catchment and suspended solids formation and sedimentation. The model input parameters are the effective diffusion coefficient in bottom sediments, depth of the completely mixed layer, the distribution coefficient in the sediment-water system, the runoff coefficient, sedimentation rate, and deposition density. Values of all these parameters can be independently estimated or measured in a short-term experiment. Given negligible runoff and sedimentation, the dynamics of radiocaesium in lake water is described by a simple equation with only one unknown parameter. This allows us to make long-term predictions on the basis of a series of measurements carried out during the relatively short period. The model was tested against 137Cs activity concentrations measured between 1993 and 1999 in Svyatoe lake in the Bryansk region of Russia. Calculated and measured activity concentrations are in good agreement.

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A method for quantitative assessment of 137Cs availability to plants in forest ecosystems on the basis of soil properties has been developed. It is shown that the experimental dependencies of 137Cs soil-to-plant transfer factor (TFag) for fern and bilberry on the bioavailability factor calculated on the basis of soil characteristics of root layer: 137Cs exchangeability, exchangeable Ca, effective selectivity coefficient, were satisfactory described by linear function. The advantage of the proposed method is that the necessary soil characteristics can be taken from the reference literature, evaluated using empirical correlations or determined with standard agrochemical procedures.

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A method of calculation of radiocaesium concentration ratio in plants and mushrooms as a function of radionuclide and soil properties distribution within the root (myzelium) zone is presented. The method allows to predict the long-term dynamics of radiocaesium content in field and forest plants and mushrooms.

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A method of calculation of radiocaesium uptake by forest mushrooms as a function of soil properties is presented. Calculated value of 137Cs transfer factor for Xerocomus badius in the contaminated area of Bryansk Province of Russia is in a good agreement with experimental data.

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A new 44-kD, C-type mannan-binding lectin (MBL-C) consisting of two identical subunits was isolated from the coelomic fluid of the holothurian Cucumaria japonica. In the direct hemagglutination assay, the lectin was effectively inhibited by highly branched mannans similar in structure to yeast mannans and composed of alpha-(1-->2)- and alpha-(1-->6)-bound D-mannopyranose residues. Hemagglutination was not inhibited by mannosaccharides, common constituents of the hydrocarbon chains of "normal" glycoproteins. The lectin reaction depends on Ca2+ concentration: maximum activity of MBL-C is observed at 10 mM Ca2+. The activity of MBL-C increases in the pH range from 5 to 7 and reaches maximum at pH 7.0. The lectin is sensitive to temperature. Heating of the lectin solution at temperatures above 40 degrees C decreases activity, while incubation at 90 degrees C for 1 h leads to complete irreversible inactivation. Carbohydrate specificity, Ca2+-dependence, and amino acid composition indicate that MBL-C belongs to the C-type mannan-binding lectins. Polyclonal antibodies against MBL-C revealed its immunochemical similarity to a mannan-binding lectin from another holothurian species, Stichopus japonicus; this provides evidence for structural homology between these proteins.

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The results of preliminary studies suggest that the cytoskeletal fraction of the radial nerve of the starfish Asterias amurensis contained a 32 kDa protein, which is tissue specific. This protein was isolated from the radial nerve by preparative electrophoresis and used as an antigen for raising polyclonal antibodies. When testing these antibodies on sections of the starfish tissues, it was shown that they interact only with the proteins present in the radial nerve cells. A conclusion was drawn that the raised antibodies may be used as a cell marker when studying regeneration of the nervous system in starfish.

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Two alkaline DNases of tentacles of actinia Radianthus macrodactylus, referred to as alk DNase I and alk DNase II, respectively, have been purified up to apparent homogeneity with consecutive column ion exchange chromatography and gel filtration. Both enzymes have a lot of common properties, such as the ability to hydrolyze very effectively p-nitrophenyl-5'-TMP and heat-denatured DNA. They both have no preferential specificity to the sugar component of the nucleic acids and effectively digest ribopolymers. Their ability to hydrolyze supercoiled DNA of the pBR322 plasmid and linear DNA of the lambda phage by "miscellaneous" exo- and endonucleolytic types of attack and to produce nucleosides, nucleotides and short oligonucleotides suggests their similarity with phosphodiesterase I (5'-exonuclease, oligonucleate 5'-nucleotidohydrolase; E.C. 3.1.4.1), isolated from rattle snake Crotalus adamenteus venom. Alk DNase II has been revealed to have some uncommon properties, such as phosphomonoesterase and hemolytic activities. The protein causes a very potent lysis of human and rabbit erythrocytes. The ability of alk DNase II to precipitate some components of normal human and rabbit blood serum as well as the inhibition of this reaction by fucose but not by another monosaccharides suggest the enzyme to have a lectin-like activity. The appearance of only one protein band during electrophoresis of alk DNase II in denaturation conditions suggests that all activities are inherent to the same molecule of protein. The possible role of alkaline DNases in the toxic effect of burning by actinia tentacles is discussed.

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The "Wash-off" scenario is designed to test models concerned with the movement of trace contaminants from terrestrial sources to bodies of water, specifically the contamination of surface water by wash-off of radionuclides initially deposited onto soils. Particular emphasis is placed on chemical speciation and on the geochemical and geophysical processes affecting transfer of contaminants from soil to water. The scenario gives descriptions of two experimental plots near the Chernobyl power plant, one using heavy rain and one using snow melt, together with characteristics of the initial aerial deposition of the radionuclides and data on topography, soil type and characteristics, and time-varying precipitation. Predictions are requested for (1) the vertical distribution of concentrations of exchangeable and nonexchangeable forms of 137Cs and 90Sr in the soil of the experimental plots, (2) concentrations of 137Cs and 90Sr in runoff water from the experimental plots, and (3) total amounts of 137Cs and 90Sr removed by runoff from the experimental plots. Test data (field measurements) are available for all endpoints.

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The regeneration of longitudinal muscle bands (LMBs) in the sea cucumber Stichopus japonicus was studied using light and electron microscopic and immunocytochemical methods. Previous investigations of holothurian organs showed the presence of some cytoskeletal proteins which were specific for LMBs only. One of them, the 98 KDa protein, was isolated by means of SDS-electrophoresis and used as an antigen to obtain polyclonal antibodies. When tested on paraffin sections of sea cucumber organs, the antibodies were shown to interact only with coelomic epithelial cells covering the LMBs. The antibodies were used to study LMB regeneration after transverse cutting. During regeneration no signs of myocyte dedifferentiation or mitotic division were observed. In the wound region, damaged myocytes degenerated and muscle bundles desintegrated. However, the coelomic epithelial cells dedifferentiated and began to invade the LMB. Just beneath the surface these cells formed clusters (muscle bundle rudiments). The number and size of the clusters gradually increased, the cells lengthened and developed contractile filaments. These observations suggest that new muscle bundles arise from coelomic epithelial cells covering the LMBs. The migration of coelomic epithelial cells into the damaged LMBs and their myogenic transformation are the basic mechanism of holothurian muscle regeneration.

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Field and laboratory experiments have been used to study the behaviour of long-lived radionuclides in the zone affected by the Chernobyl accident. Speciation of 90Sr and 137Cs in soils and bottom sediments was determined. The principal distinction of the Chernobyl fallout was that it contained a relatively small proportion of exchangeable forms because a considerable fraction of the radionuclides was incorporated as part of the insoluble fuel particles. Disintegration of fuel particles in soils and bottom sediments results in transition of non-exchangeable forms into exchangeable forms. Radionuclide species have different pathways and rates of migration in soils and bottom sediments. Migration of each chemical form was described by a convective-dispersive equation taking into account transformation processes of radionuclide species in soils or bottom sediments. Adsorption of 90Sr and 137Cs in the environment is controlled by the cation-exchange capacity and the selectivity of the solid phase (i.e., soil, bottom sediments and suspended matter) and the cationic composition of the liquid phase (i.e., soil solution, surface run-off and river or lake water). The corresponding parameters for the processes were obtained.

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The influence of temperature and pH on the spatial structure of EPA-1NG has been studied by means of circular dichroism and differential UV-spectroscopy, indicating the molecule to consist mainly of beta-structures. A conformational transition in the molecule was observed within the range of 40-50 degrees C. The further temperature elevation (up to 70 degrees C) was accompanied to the complete distortion of the parent conformation, which is reversed after cooling down to 20 degrees C. A correlation of the spectral data with the antigenic activity of genuine EPA-1NG and its carboxymethylated, heat-degraded and pH-denatured derivatives demonstrates that some antigenic determinants of EPA-1NG appear to be topographic.

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General chemical and immunochemical characterization of human embryonic prealbumin-1 (EPA-1) isolated from abortive blood is presented. EPA-1 was found to exist as glycosylated and non-glycosylated forms, which are immunochemically identical. Sugar moiety of the glycosylated form contains residues of fucose (3.0%), mannose (3.2%), galactose (7.8%), N-acetylglucosamine (5.4%), N-acetylgalactosamine (1.2%) and N-acetylneuraminic acid. Using methylation studies, types of bonds between the sugar residues were elucidated.

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alpha 1-Acid glycoprotein (AGP) samples, viz., normal AGP (nAGP) and embryonic AGP (eAGP), were isolated from plasma of normal donor blood and abortive human blood, respectively. The materials possess similar amino acid composition and immunochemical properties. However, structural patterns of their sugar moieties differ substantially. nAGP contains only N-glycosidically bound sugar chains, whereas on eAGP some sugar chains are linked through O-glycosidic bonds. Disaccharide GlcNAc beta 1----3Gal was identified in considerable amounts in HF-solvolysate of eAGP but only as traces in nAGP.

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