Radioactive caesium in British mushrooms

Summary

Thirty-four different taxa of larger fungi have been analysed for their content of caesium 137 over a 3 year period. The majority of the material has been collected from various sites in Central Scotland; 38% of the collections were from North Wales and Merseyside. Comparison has been made between the same species from different sites and different species from the same site. It has also been possible to analyse the same species from the same plot on two consecutive years. The levels of caesium 137 in the fungal species analysed were extremely low when compared with their counterparts in Central Europe and it is concluded that the Chernobyl incident had little effect on the accumulation by these fungi of this radionuclide. There is no evidence that edible species accumulate caesium 137 at levels considered to be dangerous for consumption.     

Soaking in Cs2SO4 reveals a caesium-aromatic interaction in bovine-liver rhodanese

Soaking crystals of rhodanese (thiosulphate:cyanide sulphurtransferase) in 2 M caesium sulphate reveals three caesium binding sites of this enzyme. One of these had been described before as a binding site for sodium ions and is located in a cleft close to the active site. In this site the monovalent cation is coordinated by five oxygen atoms. The first additional binding site seems to be quite special. The caesium ion is bound to the phenyl ring of a tryptophan residue. It is further liganded by two oxygen atoms. The third binding site is a result of crystal packing effects: caesium is liganded by four oxygen atoms, provided by two rhodanese molecules and one sulphate ion. It is likely that the binding of caesium affects the fluorescence of the tryptophan residue with which it interacts. Such possible effects should also be kept in mind when caesium ions are used as a quencher in fluorescence studies of proteins in general.     

Extraction of caesium from mosses and incorporation into an oxalate crystalline lattice

The ratios of stable and radioactive isotopes in the environment are not constant and their effects on living organisms are not the same. Whilst radionuclides can be monitored by measuring their radioactivity levels, it is also important to determine the stable isotopes. The method described in this paper represents a simple and cheap process by which to extract caesium from moss, without significant destruction of the plant, and to incorporate the isolated caesium into a water-soluble crystal. Ammonium oxalate and phosphoric acid are water-soluble substances at 5% concentration but, when the solutions are combined, crystallisation occurs. Crystals were estimated to contain 68.30% O, 20.98% C, 4.68% H, 6.04% N and less than 0.01% P, corresponding to NH4HC2O4 x H2C2O4 x 2H2O (C4H11NO10). The crystal mass did not vary with the species of moss, although the effectiveness of caesium extraction did. Typically, 73.0 +/- 6.1% of the solubilised caesium was entrapped within the crystals.     

The use of equilibrium-density-gradient methods for the preparation and characterization of blood-group-specific glycoproteins

1. The method of sedimentation equilibrium in a gradient of caesium chloride has been applied to the preparation of blood-group-specific glycoproteins from human ovarian-cyst fluids: it is shown that virtually complete separation from contaminating protein is easily accomplished in a single step. 2. The glycoproteins isolated in this way have been characterized by analytical density-gradient experiments in both caesium chloride and caesium sulphate and values of the buoyant density, selective solvation and apparent molecular weight have been obtained. 3. In some cases, materials prepared from the same cysts by solvent extraction methods have also been characterized in these terms. 4. The selective solvation values are about 0.1 and 0.5g of water/g of glycoprotein in caesium chloride and caesium sulphate respectively. 5. The apparent molecular-weight values are much lower than the weight-average molecular weights, and it is shown that the origin of the discrepancy is heterogeneity in density of the glycoproteins. 6. Some sources of error in the interpretation of density-gradient schlieren patterns are examined.     

DNA nuclear satellites of the genus Brassica]

Distribution of nuclear DNA of nine species of the genus Brassica in caesium chloride density gradient has been studied. It has been shown that the amount of the satellite DNA component with the density of 1.704 g.cm-3 varies within a wide range. It is completely absent in B. oleracea and its amount reaches 37% in B. nigra. The other species have an intermediate position. The absence of the latent satellite DNA component in B. oleracea has been shown by equilibrium ultracentrifugation in Cs2SO4 density gradient containing Hg++. Denaturation-renaturation properties of the nuclear DNA of B juncea have been studied.     

Attempts to isolate parvovirus from human acute non-bacterial gastro-enteritis cases

It has been suggested that the causative agent of human acute non-bacterial gastro-enteritis, based on morphology, buoyant density in caesium choloride, resistance to acid, and reactions to ether and heat, may be a parvovirus. Using conditions optimal for parvovirus multiplication, attempts were made to isolate a parvovirus from such specimens. Results were negative indicating that the agent is not a parvovirus.     

Biological consequences of Chernobyl: 20 years on

The disaster at the Chernobyl nuclear power plant in 1986 released 80 petabecquerel of radioactive caesium, strontium, plutonium and other radioactive isotopes into the atmosphere, polluting 200 000 km(2) of land in Europe. As we discuss here, several studies have since shown associations between high and low levels of radiation and the abundance, distribution, life history and mutation rates of plants and animals. However, this research is the consequence of investment by a few individuals rather than a concerted research effort by the international community, despite the fact that the effects of the disaster are continent-wide. A coordinated international research effort is therefore needed to further investigate the effects of the disaster, knowledge that could be beneficial if there are further nuclear accidents, including the threat of a "dirty bomb".     

The architectural development of the early mammalian heart

The period 8–10 days post-coitum represents a most critical one in the development of the heart of the mouse; a necessary prerequisite in the concomitant development of the entire embryo. During this period the four chambers which ultimately form the mature heart become defined, as does the bulbus arteriosus. The development observed in the atria and bulbus is less than that in the ventricles. It has been found that, following the establishment of a thin muscular wall to the chambers, the main muscular development in the ventricles and bulbus at this stage is trabecular in form, and the myofibrillar organization in the trabeculae is in general more advanced than in the primitive myocardial wall. Thus it appears that at this stage most of the pumping force is supplied by the trabecular musculature.     

Formation of the circulatory bed of the neuromuscular spindles in forearm and hand muscles]

The data are presented on the formation and main constitutional principles in the blood supply of the neuromuscular spindles in the human forearm and hand during embryogenesis and early postnatal life. It has been stated that the neuromuscular spindles posses their own microcirculatory bed which is formed by the vessels of the surrounding muscular tissue, tends to separate in the course of development and subdivides into two parts: extracapsular and intracapsular. The vessels of the extracapsular part form dense capillary nets on the external surface of the capsule and follow extracapsular parts of the intrafusal muscular fibres. The intracapsular vessels either cover the internal surface of the capsule, or adjoin the intrafusal muscular fibres, or else run in the free subcapsular space.     

Transport of DNA from Lymphocytes to Fibroblasts in Culture

The exchange of radioactivity between lymphocytes, labelled with (³H) thymidine after stimulation with Concanavalin A, and recipient V79 fibroblasts in culture was studied. The radioactive material involved in this exchange was macromolecular deoxyribonucleic acid as well as its breakdown products. This deoxyribonucleic acid from lymphocytes localised in the nuclei of the host cells soon after contact between donor and recipients. This occurred even when the V79 fibroblasts were confluent at high cell density, and thus in a steady, non-growing state with respect to cell numbers.
The fate of the radioactive donor lymphocyte deoxyribonucleic acid, substituted with bromodeoxyuridine, was followed in the recipient cells by analysing its buoyant density in caesium chloride gradients. This deoxyribonucleic acid was found to become associated with the nuclear deoxyribonucleic acid of the host cells, involving both retention of relatively intact donor deoxyribonucleic acid as well as its breakdown and re-utilisation for host cell deoxyribonucleic acid synthesis. Nongrowing recipient cells were found to retain the donor deoxyribonucleic acid in relatively intact form for much longer periods than when the same cells were in logarithmic growth phase.     

A taxonomic and nomenclatural note on Hieracium caesium (Asteraceae)

The only specimen suitable for typification of Hieracium caesium was discovered in UPS and is here designated as the lectotype. This name appears to have been misapplied and superfluous when originally published at specific rank, but is legitimate according to Art. 52.3. Correct names proposed for three species of the group Caesia (H. caesium = H. basifolium, H. laeticolor and H. plumbeum) are given with infraspecific variants and some more important synonyms. The names H. caesium subsp. laeticolor, H. imitans, H. caesium var. nemorum, H. plumbeum are also lectotypified. Two new combinations H. caesium var. basifolium and H. caesium var. imitans are proposed.     

The Foliar Uptake and Translocation of Caesium

A study has been made of the foliar uptake and translocationof caesium-137 by pea plants which have been grown for a periodin either the light or the dark. Keeping plants in the darkreduces both processes, and also reduces the proportion of mobilecaesium which is transported downwards. Other experiments involved darkening only parts of the plantand also the use of various metabolic inhibitors. These showedthat the reduction in foliar uptake and translocation in thedark was connected with changes in the carbohydrate metabolismof the leaf to which the caesium was applied. They further suggestedthat a metabolically controlled process was involved in thetransfer of caesium from the mesophyll into the phloem of theleaf veins. Changes in the distribution of caesium were alsogoverned in some way by changes in the carbohydrate metabolismof the ‘source’ leaf.     

137Cs penetration by contact exchange through isolated plant cuticles: cuticles as asymmetric transport membranes

The penetration of ¹³⁷Cs by contact exchange through cuticular membranes from the adaxial surface of leaves of Pyrus communis and Prunus cerasus has been investigated. The resistance of the cuticles to the caesium penetration was dependent on the counter-ions associated with the fixed negative ion exchange sites in the membrane. The mobility of hydrated potassium ions and their tenuous connection to -COOH^?-groups in the membrane encouraged caesium permeation in contrast to cuticular membranes with predominantly protonized ion exchange sites. Divalent calcium ions caused a strong reduction (4–20 times) of the caesium permeability which is decisive for the calculation of the caesium uptake by the intact leaf. Under these conditions, a penetration rate of the deposited caesium of 0·11±0·05% h^?1 for pear cuticles and of 0·036±0·025% h^?1 for cherry cuticles was measured after the adjustment to steady state conditions. Approximately 12–24% and 4·5–7·5% of initially retained caesium could be absorbed by the leaves of pear and cherry, respectively, in a rain-free period of 7 d in the area of Munich after wet deposition of fallout from the Chernobyl reactor accident. Furthermore, the caesium penetration from the physiological inside to the outside of the membrane was found to be smaller by a factor of 100–150 compared with that of the opposite direction.     

Calpain 3: a key regulator of the sarcomere?

Calpain 3 is a 94-kDa calcium-dependent cysteine protease mainly expressed in skeletal muscle. In this tissue, it localizes at several regions of the sarcomere through binding to the giant protein, titin. Loss-of-function mutations in the calpain 3 gene have been associated with limb-girdle muscular dystrophy type 2A (LGMD2A), a common form of muscular dystrophy found world wide. Recently, significant progress has been made in understanding the mode of regulation and the possible function of calpain 3 in muscle. It is now well accepted that it has an unusual zymogenic activation and that cytoskeletal proteins are one class of its substrates. Through the absence of cleavage of these substrates, calpain 3 deficiency leads to abnormal sarcomeres, impairment of muscle contractile capacity, and death of the muscle fibers. These data indicate a role for calpain 3 as a chef d'orchestre in sarcomere remodeling and suggest a new category of LGMD2 pathological mechanisms.     

Assignment of the heterogeneous static and time-resolved tryptophan fluorescence of 3-phosphoglycerate kinase

The heterogeneous fluorescence of yeast 3-phosphoglycerate kinase, a hinge-bending enzyme with two tryptophan residues, has been resolved into three emission components using steady-state and time-resolved studies of the fluorescence quenching by acrylamide, iodide and caesium ions at different emission wavelengths. The buried Trp-333 has a blue-shifted heterogeneous emission spectrum characterised by three fluorescence lifetimes, and is inaccessible to quenchers. The surface Trp-308 also has a heterogeneous emission with multiple lifetimes. The emission of Trp-308 can be separated into a blue-shifted emission accessible to acrylamide and caesium only, and a red-shifted emission accessible to all three quenchers.     

The preparation of alcohol dehydrogenase and glyceraldehyde 3-phosphate dehydrogenase from baker''s yeast

A procedure has been developed for the preparation of alcohol dehydrogenase and glyceraldehyde 3-phosphate dehydrogenase from the same sample of baker's yeast. The two enzymes were obtained in good yield in a pure crystalline form. The method minimizes the work involved in preparing the two enzymes and would be of particular advantage for preparing the enzymes in radioactive form from yeast grown in a radioactive medium.     

Structure of the B DNA cationic shell as revealed by an X-ray diffraction study of CsDNA. Sequence-specific cationic stabilization of B form DNA

Synchrotron radiation diffraction data for phage T2 CsDNA fibres have been used to determine the co-ordinates of the caesium ions in crystalline B form DNA. The R value is 0.16 for an optimized structure. The caesium ions are distributed equally between the narrow and wide grooves of B DNA and are located close to the dyad axes lying between the planes of adjacent base-pairs. On the wide-groove side the cations are separated from the nearest phosphate atoms by a hydration layer one to two water molecules thick. In the narrow groove the cations are directly co-ordinated to the base atoms and, for six out of ten possible DNA stacking types, form chelation complexes: O-2(Pyr)-Cs+-O-2(Pyr), O-2(Pyr)-Cs+-N-3(Pur) or N-3(Pur)-Cs+-N-3(Pur), which stabilize the B conformation. The steric properties of such complexes as estimated for different base sequences and for different ions are consistent with the structural behaviour of double-helical polynucleotides with different base sequences, as experimentally observed.     

The resistance of muscle larvae of Trichinella spiralis to exposure to low temperatures]

It has been shown that the resistance of muscular larvae of Trichinella spiralis to the effect of low temperatures depends on the conditions of freezing and composition of media possessing cryoprotective properties. It has been established that under optimal conditions (medium of microenvironment, conditions of freezing) during the storage in liquid nitrogen muscular larvae of T. spiralis preserve 50 to 60% of their resistance by the character of mobility and 11 to 15% by their capacity for reproduction. The question of creation of low-temperature bank for Trichinella is discussed.     

Fractionation of a hyaluronic acid preparation in a density gradient: The isolation and identification of a chondroitin sulphate

1. Following the suggestion of Nichol, Ogston & Preston (1967) that hyaluronic acid, prepared by filtration from ox synovial fluid, contains a component of high density, such material has been detected and isolated by equilibrium sedimentation in a density gradient of caesium chloride. 2. This material (fraction III) has been characterized as a chondroitin sulphate-protein complex of average molecular weight about 250000. Its amino acid pattern is characteristic of such complexes present in cartilage. It contains a proportion of glucosamine (as well as galactosamine); this is not due to contamination with hyaluronic acid. 3. Preliminary findings on fraction I (low density) and fraction II (intermediate density) suggest that these consist chiefly of protein and hyaluronic acid respectively.     

Surface water radioactive pollution in South Yakutia anthropogenic landscapes

The Propadayushchii Brook that drains the radioactive waste piles at the Kurung-1 site (mine 2) of the Yuzhnoe deposit serve as an illustration of our studies of the chemical composition and assessment of the radioactive pollution level of surface waters in the Elkon uranium ore-bearing region in the territory of South Yakutia. It has been noted that the main source of anthropogenic pollution of the surface waters in this region is the radioactive refuse piles of rocks carried to the hypergenesis zone as a result of long-term and large-scale geological surveys for radioactive raw material.