Accumulation of mercuric selenide granules in the liver of Odontocetes (Mammifers, Cetacea): a possible method of detoxification of methylmercury by selenium]

In Mediterranean Cetaceans, concretions of pure mercuric selenide are found in the connective tissue of the liver. Their presence explains that high levels of mercury and selenium coexist with low level of methylmercury. The selenide could be produced parallel with demethylation of mercury, a process leading to the fossilization of mercury and partially of selenium under the form of a non biodegradable component.     

Microbial dissolution and stabilization of toxic metals and radionuclides in mixed wastes

Summary Microbial activity in mixed wastes can have an appreciable effect on the dissolution or precipitation of toxic metals and radionuclides. Fundamental information on microbial dissolution and stabilization (immobilization) of toxic metals and radionuclides, in particular actinides and fission products, in nuclear wastes under various microbial process conditions, e.g., aerobic, denitrifying, iron-reducing, fermentative, sulfate-reducing, and methanogenic conditions is very limited. Microbial transformations of typical waste components such as metal oxides, metal coprecipitates, naturally occurring minerals, and metal organic complexes are reviewed. Such information can be useful in the development of 1) predictive models on the fate and long-term transport of toxic metals and radionuclides from waste disposal sites, and 2) biotechnological applications of waste treatment leading to volume reduction and stabilization as wall as recovery and recycling of radionuclides and toxic metals.     

Complexing agents from microorganisms

Summary The majority of extracellular complexing ligands produced by microorganisms are summarized as being of low molecular mass (<10,000 daltons) and are usually released as part of metal detoxification processes. These exudates appear to exhibit strong metal-binding characteristics, often reducing metal toxicity. Under certain conditions microbes produce metal-specific compounds of low molecular mass called siderophores; although these are normally specific for iron they also have relatively high affinities for radionuclides such as Pu and facilitate their uptake into cells. The occurrence of specific actinide complexing agents has been recorded.The breakdown of lignins and cellulosic material produces large macromolecular compounds called humates. These contain multiligand sites and display a wide range of complexing abilities. They form both soluble and insoluble complexes with toxic elements with various results. Humates also considerably influence adsorption of metals to substrate surfaces and at high pH may compete with OH-ions for metal binding.As well as with extracellular ligands, metals can interact directly with microorganisms by accumulation in subcellular compartments or by adsorption on bacterial surfaces.     

Calcite growth under controlled diffusion

Summary The growth of calcite was studied in a gelatin-gel medium under variable environmental conditions by 2 different methods. The results suggest that the organic matrix, the temperature, the diffusion fluctuation depending on ionic concentrations, and the presence of additives exert a fine control on the evolution of single crystals, polycrystalline aggregates, and highly structured concretions of calcite.Presented at the 22nd Canadian Conference on Pharmaceutical Research, Montreal (Quebec), Canada, 16 May 1975.Acknowledgments. This work was supported, by the Medical Research Council of Canada. — The authors are indebted to Dr J. M. Dorlot, Department of Metallurgy, Ecole Polytechnique, Montreal, for the use of the scanning electron microscope and thanks are due to Mr J. Claudinon for his technical assitance.     

Cadmium in the atmosphere

Summary Cadmium is present naturally in the air mainly as a result of volcanic emissions and release by vegetation. Anthropogenic sources, which overall give rise to emissions one order of magnitude greater than natural sources, are largely primary non-ferrous metals production and waste incineration. Measured concentrations of airborne cadmium are typically < 1 ng m^–3 at remote sites, 0.1–10 ng m^–3 at rural sites and 1–100 ng m^–3 at urban and industrial sites, dependent upon the nature and proximity of local sources. Particle sizes are generally <2 m, and often considerably smaller, consistent with an anthropogenic source and a long atmospheric life-time. Cadmium deposition to the land occurs with fluxes varying from 0.05 ng cm^–2 month^–1 in Greenland to circa 1000 ng cm^–2 month^–1 in the vicinity of major industrial sources. The possible significance of a motor vehicular source of airborne cadmium is also reviewed.     

湖南省有色金属产业竞争力研究

根据区域经济学及产业经济学的理论，分析了湖南省有色金属产业的发展现状，建立了有色金属产业竞争力评价指标体系，运用主成分分析法将湖南与中部五省进行评价和比较。结论是湖南省有色金属产业竞争力属于中等偏上水平，总的经济效益偏低。提出了有效提升湖南省有色金属产业竞争力的政策建议.     

Characteristics of nuclear and fossil energy wastes

Summary The radionuclides and toxic metals in transuranic, low-level radioactive coal combustion, and coal conversion wastes are summarized. These wastes also contain a variety of organic compounds, some of which can support indigenous microbial activity resulting in solubilization or stabilization of toxic metals and radionuclides.     

Effects of the metals,Be, Fe,Cu and Al,on the mobility of immunoglobulin receptors

Summary Cap formation in mouse spleen cells induced by antiimmunoglobulin was inhibited by the metals Be, Fe, Cu and Al. Be was especially strong as an inhibitor of cap formation. It is suggested that these metals might change the mobility of the membrane and have some biological effects on the cross association of antigen receptors when B lymphocytes are attached by them.     

The roots of the silver tree: Boyle,alchemy, and teleology

Though Robert Boyle called final causes one of the most important subjects for a natural philosopher to study, his own treatise on the subject, the Disquisition about Final Causes, has received comparatively little scholarly attention. In this paper, I explicate Boyle's complex argument against the use of teleological explanations for inanimate bodies, such as metals. The central object of this argument is a mysterious allusion to a silver plant. I claim that the silver plant is best understood as a reference to alchemical product: the Arbor Dianae, an offshoot of George Starkey's recipe for the Philosophers' Stone. Then, I show how the context of alchemy not only clarifies Boyle's argument but also places it within a wider dialectic about matter and teleology. I then contrast the parallel arguments of Boyle and John Ray on the question of whether metals have divine purposes and show that the difference is explained by Boyle's belief in the transmutation of metals.     

Observational defects in eighteenth-century British telescopes

Among the several remarkable properties of mercury is that it dissolves many of the metals (but not iron), forming amalgams. It was the recognition of the ready formation of gold and silver amalgams that led to the extraction of precious metals by the amalgamation method. In this article I trace some of the historical aspects associated with the development of the European amalgamation process, first devised by Ignaz von Born in the 1780s. In particular, I describe an international gathering of experts in mining and metallurgy which was held at Skleno in Slovakia in 1786, and the founding there of a society for mining sciences called ‘Die Societät der Bergbaukunde’.     

Biologische und chemische Wege zur Anreicherung von Spurenelementen

Summary Using as examples hemovanadin, the vanadium-containing blood pigment of the ascidianPhallusia mamillata, and ferritin, the protein for iron storage in mammals, pathways for the concentration of vanadium and of iron are described: These have been realizedin vitro and may occurin vivo. The uptake and concentration of heavy metals in nature seems to occur by means of complexing agents.High molecular weight, insoluble chelating substances which are able to bind metal ions, especially uranium and copper selectively, have been synthesized. Recovery of the metals is possible without destruction of the chelating groups, and, as in the case of ion-exchange resins, repeated cycles can be carried out without diminishing the metal-binding capacity.     

Transition metals in an experimental tumour system.

In this report we present an analysis by atomic absorption spectrometry of some of the transition metals Fe, Zn, Cu, Mn, Co, and Ni in tissues and nuclear fractions in an experimental tumour system.     

Antimicrobial activity of metal derivatives of sulfonamides

Antimicorbial activities of a series of metal derivatives of some sulfa drugs were examined. Such metal derivatives showed higher antimicorbial activity than the parent sulfa drugs, and among the metals, gold derivatives are seen to be the most effective.     

High levels of transition metals in dinoflagellate chromosomes

X-ray microanalysis of fixed, sectioned chromosomes of the dinoflagellates Glenodinium foliaceum, Prorocentrum micans and Amphidinium carterae has revealed high levels of iron, nickel, copper and zinc. We report high levels of these transition metals in association with chromosomes in intact eukaryote cells.     

Ambivalent effect of protein binding on computed distributions of metal ions complexed by ligands in blood plasma.

Although the absolute concentrations of metal complexes in blood plasma are controlled by protein binding, the percentage distribution of transition metal ions amongst low molecular weight ligands is not. Thus, computer simulations which omit protein equilibria can nevertheless afford reliable information about such metals in the biofluid.     

Laccases of prokaryotic origin: enzymes at the interface of protein science and protein technology

The ubiquitous members of the multicopper oxidase family of enzymes oxidize a range of aromatic substrates such as polyphenols, methoxy-substituted phenols, amines and inorganic compounds, concomitantly with the reduction of molecular dioxygen to water. This family of enzymes can be broadly divided into two functional classes: metalloxidases and laccases. Several prokaryotic metalloxidases have been described in the last decade showing a robust activity towards metals, such as Cu(I), Fe(II) or Mn(II) and have been implicated in the metal metabolism of the corresponding microorganisms. Many laccases, with a superior efficiency for oxidation of organic compounds when compared with metals, have also been identified and characterized from prokaryotes, playing roles that more closely conform to those of intermediary metabolism. This review aims to present an update of current knowledge on prokaryotic multicopper oxidases, with a special emphasis on laccases, anticipating their enormous potential for industrial and environmental applications.     

Hemolysis and peroxidation in heavy metal-treated erythrocytes; GSH content and activities of some protecting enzymes

Summary The activities of superoxide dismutase, catalase and glutathione peroxidase, and the level of reduced glutathione, were measured in heavy metal-treated erythrocytes. The hemolytic metals were found to significantly deactivate both catalase and glutathione peroxidase and to decrease the level of reduced glutathione, thus providing suitable conditions for the development of peroxidation.     

Gluconolactonase: a zinc containing metalloprotein

Summary A metal analysis of bovine hepatic gluconolactonase indicates the presence of at least 1 atom of tightly bound zinc per enzyme subunit in this hexameric protein. Other divalent metals are present in lesser quantities and are subject to removal by EDTA. Activation energies for the manganese and magnesium catalyzed reactions are 5.3 and 11.0 kcal/mole, respectively.     

Antimicrobial activity of metal derivatives of sulfonamides

Summary Antimicrobial activities of a series of metal derivatives of some sulfa drugs were examined. Such metal derivatives showed higher antimicrobial activity than the parent sulfa drugs, and among the metals, gold derivatives are seen to be the most effective.We wish to thank for the material supplied by the Central Research Laboratories, Meiji Seika Kaisha, Ltd, for antimicrobial assay.     

Methods of metal incorporation into intracellular granules

Summary The hepatopancreas of the garden snail (Helix aspersa) contains basophil cells which produce intracellular granules of CaMgP₂O₇. A variety of metals are incorporated into these granules either by direct substitution or by the synthesis of new pyrophosphate material.Supported by NERC grant GR3/3063.