Transferase activity of endo-β-1,6-glucanases from the crystalline stalks of bivalve marine molluscs

It has been shown that endo-β-1,6-glucanases from marine molluscs perform a transglycosylation reaction. When o-nitrophenyl β-D-glucopyranoside (Np glucoside) was used as acceptor, among the newly formed products Np gentiobioside, -trioside, and -tetraoside with a total yield of up to 20% on the initial Np glucoside were detected.     

90Sr, 137Cs, 238Pu, 239+240Pu and 241Am levels in terrestrial and marine ecosystems around the Italian base in Antarctica

During the last 14 years the Radioecology Laboratory of Parma University and the General Chemistry Institute of Urbino University collaborated on a radioecological programme having the aim to observe the evolution of antropogenic radioactivity in Antarctica in the period 1987-2001. The artificial radionuclides considered were ⁹⁰Sr, ¹³⁷Cs, ^239+240Pu,²³⁸Pu and ²⁴¹Am. The contamination seems to be higher in the continental environment rather than in the marine one. Mosses, algae and lichens showed the highest values for all radionuclides analyzed. The results prove that the Antarctic continent is interested by radioactive pollution. As far as ¹³⁷Cs is concerned, a progressive decrease was observed.     

Trace metals in biological matrices

A report on the 9th annual meeting of the Federation of Analytical Chemistry and Spectroscopy Societies held at the Franklin Plaza Hotel, Philadelphia, PA on September 19–24, 1982.     

Biophysiological changes observed in members of the Italian expeditions to Antarctica

The objective of this study was to investigate whether food consumed by individuals working in Antarctica is adequate and sufficient, from the nutritional viewpoint, to sustain life in extreme environments. Malnutrition can be the cause of both health impairment and reduction in psychological and physiological efficiency. The study involved individuals from two subsequent expeditions in Antarctica, namely, 34 subjects (group A) from the Italian Mario Zucchelli Base (MZB) in October-November 2002 and 30 subjects (group B) from the Italian-French Concordia Station (CS) between November 2003 and January 2004. Each group of volunteers consisted of subjects with a controlled diet as well as of subjects with a free diet. Blood and hair samples were taken just before the expeditions (with the purpose of setting the baseline) and during the last week spent in Antarctica. Samples were then shipped to Italy to be analyzed, while the body composition and the hydration status were measured on the spot by Bio-Impedentiometric Assay (BIA). Anthropometrical measurements were carried out weekly. The data obtained were statistically assessed by using the Student t-test for correlated samples and showed, in all subjects, alterations of the hypothalamic-pituitary-thyroid axis, of blood parameters and of some components of the hair along with some variations of the psychological behaviour. The variations observed can probably be ascribed to environmental conditions and a combination of factors such as isolation, atmospheric conditions and prolonged presence of daylight.     

Trace chemistry of toxic metals in biomatrices

Summary Based on differential pulse anodic stripping voltammetry (DPASV) at the HMDE after low temperature ashing of the biomatrix in an oxygen plasma a versatile and reliable method for the simultaneous determination of the toxic trace metals Cd, Pb and Cu in blood has been developed. The high sensitivity combined with high precision and established accuracy is demonstrated by a number of data from extended studies with human whole blood. The pronounced reliability has been secured by the quantitative elucidation and the subsequent rather efficient suppression of the contamination sources largely concentrated in the prior digestion stage. The still remaining contamination interference sets the present determination limits in whole blood to 4 ppb for Pb and 0.1 ppb for Cd with R.S.D. of 20–30%. Accuracy was further confirmed by comparing measurements with flameless atomic absorption. Improved values for the normal levels of the treated toxic metals in the blood of non-exposed persons have been obtained particularly for the rather low content of Cd. The application potentialities of this voltammetric approach in environmental studies of toxic trace metals able to form an amalgam are much more extended. While biomatrices as body fluids, organs, organisms, plant material and food require prior low temperature ashing direct voltammetric determination and even speciation can be performed down to the ultra trace level in samples from inland waters and the sea.

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Spurenchemie toxischer Metalle in biologischen MatricesII. Voltammetrische Bestimmung von Spurengehalten an Cadmium und anderen toxischen Metallen in menschlichem Blut

Zusammenfassung Eine neue zuverlässige voltammetrische Methode zur Simultanbestimmung des Spurengehaltes der toxischen Metalle Cd, Pb und Cu im Blut wurde ausgearbeitet. Nach niedertemperaturiger Veraschung der Biomatrix im Sauerstoffplasma erfolgt die Bestimmung mit Hilfe der differentiellen pulspolarographischen Version der inversen Voltammetrie am hängenden Quecksilbertropfen. Die so erreichbare große Empfindlichkeit, hohe Genauigkeit und gesicherte Richtigkeit wird durch eine größere Anzahl von Daten aus unseren ausgedehnten Untersuchungen von menschlichem Vollblut belegt. Die ausgezeichnete Zuverlässigkeit der Resultate basiert auf der quantitativen Aufdeckung und anschließenden weitgehenden Unterdrückung verschiedener Kontaminationsquellen, die vorwiegend beim Veraschungsschritt auftreten. Die noch verbleibende Kontaminationsschwelle legt gegenwärtig die Bestimmungsgrenzen auf 4 ppb für Pb und 0,1 ppb für Cd im Blut fest bei einer relativen Standardabweichung von 20–30%. Vergleichsmessungen mit der flammenlosen Atomabsorption bestätigten die Richtigkeit. Neue und sichere Werte für den Normalgehalt der untersuchten toxischen Metalle im Blut nichtexponierter Personenkreise, insbesonders bezüglich des sehr niedrigen Cd-Pegels, wurden ermittelt. Die Anwendungsmöglichkeiten dieser voltammetrischen Methodik in der Umweltforschung sind hinsichtlich toxischer Spurenmetalle, die zur Amalgambildung fähig sind, wesentlich weitergehender. Während Biomatrices, wie Körperflüssigkeiten, Organe, Organismen, Pflanzenmaterial und Nahrungsmittel, vorherige Veraschung erfordern, ist eine direkte Bestimmung und Speciescharakterisierung auf voltammetrischem Wege bis in den Ultraspurenbereich bei Proben aus Binnengewässern und in Meerwasser möglich.

Ref. [42] counts as part I in this series.     

Trace heavy metals in various Yugoslav tobaccos

Summary Levels of trace heavy metals in various kinds of tobacco are poorly studied, so their determination in this matrix is important both from the point of view of health studies connected with smoking and more general aspects of the uptake of trace elements by plants. Because of its great sensitivity, neutron-activation analysis is very suitable for determination of trace heavy metals. The great range of concentrations to be expected makes non-destructive analysis less suitable. Thus As, Cd, Cu, Hg, Mn, Sb, Se, U, V and Zn were determined by means of rapid radiochemical separations and measurement of the-ray spectra of the isolated radionuclides with an NaI detector. Iron, and manganese at higher levels, was determined spectrophotometrically. The accuracy of the results, which represent the mean value of at least two measurements for about 10 varieties of Yugoslav tobacco, was checked by the analysis of various standard reference materials and good agreement were obtained with certified or literature values. The results were compared with analyses of Kentucky IR-1 tobacco.

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Zusammenfassung Die Schwermetallspuren in verschiedenen Tabaksorten wurden bisher nur wenig untersucht. Deren Bestimmung ist sowohl für Fragen der Gesundheit der Raucher wie im allgemeinen hinsichtlich der Spurenelementaufnahme durch Pflanzen von Bedeutung. Die Neutronenaktivierungsanalyse ist für die Bestimmung von Schwermetallspuren ihrer hohen Empfindlichkeit wegen sehr geeignet. Die weiten Konzentrationsgrenzen, mit denen zu rechnen ist, lassen nicht-destruktive Analysenverfahren weniger geeignet erscheinen. Daher wurden As, Cd, Cu, Hg, Mn, Sb, Se, U, V und Zn radiochemisch rasch abgetrennt und die Gammaspektren der isolierten Radionuklide mit einem NaJ-Detektor bestimmt. Größere Mengen Eisen und Mangan wurden spektrophotometrisch bestimmt. Die Genauigkeit der Ergebnisse, die ihrerseits den Durchschnittswert von wenigstens zwei Messungen bei ungefähr 10 jugoslawischen Tabaksorten darstellen, wurde durch Vergleich mit verschiedenen Standardproben geprüft. Dabei wurde gute Übereinstimmung mit gesicherten Werten bzw. Literaturangaben erzielt. Die Resultate wurden mit Analysenwerten von Kentucky-IR-1-Tabak verglichen.

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Paper presented at the International Symposium on Microchemical Techniques, Davos, May 1977.     

Determination of heavy metals in environmental matrices sampled inside the Park of the Po Delta

Analytical results are reported for the determination of heavy metals in environmental matrices, sampled in an ecosystem inside a protected area: the Park of the Po Delta, located near the thermoelectric power station ENEL of Porto Tolle, one of the greater in Italy. The elements determined, in sediments and superficial water, are Ni and V, linked to the fuel oil combustion. However, in order to obtain a complete picture enough of heavy metals polluting load in the study areas, the following elements: Cd, Co, Cr, Cu, Fe, Mn, Pb and Zn are also determined. For all the elements, in addition to the detection limits, precision and accuracy are also given: the former, expressed as relative standard deviation (s(r)), and the latter, expressed as relative error (e), were good, being in all cases lower than 6%.     

Immunobiosensor detection of domoic acid as a screening test in bivalve molluscs: comparison with liquid chromatography-based analysis

A rapid and sensitive immuno-based screening method was developed to detect domoic acid (DA) present in extracts of shellfish species using a surface plasmon resonance-based optical biosensor. A rabbit polyclonal antibody raised against DA was mixed with standard or sample extracts and allowed to interact with DA immobilized onto a sensor chip surface. The characterization of the antibody strongly suggested high cross-reactivity with DA and important isomers of the toxin. The binding of this antibody to the sensor chip surface was inhibited in the presence of DA in either standard solutions or sample extracts. The DA chip surface proved to be highly stable, achieving approximately 800 analyses per chip without any loss of surface activity. A single analytical cycle (sample injection, chip regeneration, and system wash) took 10 min to complete. Sample analysis (scallops, mussels, cockles, oysters) was achieved by simple extraction with methanol. These extracts were then filtered and diluted before analysis. Detection limits in the ng/g range were achieved by the assay; however, the assay parameters chosen allowed the test to be performed most accurately at the European Union's official action limit for DA of 20 microg/g. At this concentration, intra- and interassay variations were measured for a range of shellfish species and ranged from 4.5 to 7.4% and 2.3 to 9.7%, respectively.     

Trace element content in relation to the body weight of the marine bivalve,Anadara granosa with special reference to the application of INAA and ICP-AES as analytical techniques

Neutron Activation Analysis (NAA) and Inductively Coupled Plasma (ICP) spectrometry were used to determine the concentration of trace metals in marine bivalveAnadara granosa. A total of 11 elements: Mg, Cl, Mn, K, Se, Br, Zn, Co, Fe, Rb, Cd and Cu were detected. Analyses were performed to examine the relationship between metal concentration and body weight. Results from both techniques show linear relationship between total metal concentration and body weight.     

Assessment of MIST Alert,a commercial qualitative assay for detection of paralytic shellfish poisoning toxins in bivalve molluscs

A recently developed commercial rapid test kit (MIST Alert) was assessed for determination of the presence of paralytic shellfish poisoning (PSP) toxins in shellfish. Several commercially important shellfish species obtained from the UK shellfish toxin monitoring program, containing a range of total PSP toxicities as determined by the mouse bioassay (MBA), were tested. The kit detected toxin in all samples containing the European Community tolerance level of 80 microg saxitoxin (STX) equivalents/100 g shellfish flesh as determined by the MBA. With one exception, the kit detected toxin in all samples that contained >40 microg STX equivalents/100 g according to the MBA. Among samples in which the MBA did not detect toxin, the kit disagreed in 25% of the tests, although further analysis by liquid chromatography (LC) and MBA of some samples confirmed the presence of toxins. These results suggest that MIST Alert may be suitable as an initial screen for PSP toxins as part of routine monitoring programs, thereby greatly reducing the number of MBAs. Trials were also performed by nonscientific personnel to evaluate the ease of use and interpretation of results obtained by MIST Alert. The results indicated that the kits could be readily used and accurately interpreted by individuals with no technical or scientific background.     

Strongly correlated electronic ground states in metals near the metal-insulator transition

The model in which positive ions in a metal are smeared into a uniform neutralizing background in which interacting electrons move is first considered at some length, especially rather near to the metal-insulator (Wiper) transition. Properties considered carefully are (a) the electronic momentum distribution as a function of background density, and (b) the pair correlation function. Features connected with both the long-range Coulombic repulsion and the transition from delocalized to localized behaviour will be highlighted in terms of (a) and (b) above. The possible use of this model as a reference state against which to consider the alkali metals, in both normal and expanded form, will then be discussed. In Na, the importance of 3s–3p hybridization will be emphasized, the Heisenberg model providing a surprisingly useful account of some bulk properties. Diffraction evidence on the degenerate electron assembly in molten Na and K will be considered in support of pronounced metallic bonding. Expanded Cs along the coexistence curve will next be treated, especially the observed magnetic susceptibility which changes from Fermi liquid behaviour to Curie-Weiss form as the critical point is approached. The crossover point is discussed in terms of heavy fermion theory and is shown to contain information about the discontinuity of the electronic momentum distribution at the Fermi surface. This discontinuity is much smaller than that in jellium (the smeared ion model above) and testifies to the importance of the electron-ion interaction at this density, which cannot be treated perturbatively. Finally, the possibility of the co-existence of molecules in metallic phases is considered, with particular reference to metallic hydrogen and metallic iodine near the metal-insulator transition. For the latter, experimental evidence can leave little doubt that there is at least a limited range of pressures over which the metallic ground state of iodine contains I₂ molecules, and some discussion of this strongly correlated state will be included.     

Radioecological Research on the Marine Environment Facing the Italian Base in Antarctica (1989–91)

Abstract

The results of the analysis of both natural (Th-232, U-238 and K-40) and artificial (Cs-137) radioactivity contained in samples collected during the 1989–90 and 1990–91 PNRA Scientific Campaigns in the Terra Nova Bay (Ross Sea) marine ecosystem, are presented in this paper. The data refers to samples of sea water, pack water, sediments and organisms belonging to demersal ichthyofauna (Pagothenia bernacchii, Chionodraco hamatus) and soft bottom macrofauna (Adamussium colbecki) collected in different coastal and off shore stations of the area investigated. Some sea water samples collected on the way to subAntarctic areas were also considered. The radiocontamination detected in sediments was correlated to the quantities of organic matter, organic carbon and nitrogen contained in the samples. Additionally, Cs-137 concentration factors were calculated for the different biological specimens and their anatomical components. Data values, with special consideration for anthropogenic Cs-137, are compared to results obtained from similar matrixes collected in the Northern Hemisphere in temperate waters before and after the accident at the Chernobyl nuclear plant.     

One metabolite, two pathways: convergence of polypropionate biosynthesis in fungi and marine molluscs

Structural similarity or even the identity of polyketide compounds does not necessarily imply unique biosynthesis. Feeding experiments with a (13)C labeled precursor establish that the C(3) units in 7-methyl-cyercene-1 (1) are derived from intact propionate in the marine mollusc Ercolania funerea. The same compound in the terrestrial fungus Leptosphaeria maculans/Phoma lingam is synthesized by an acetate/SAM pathway thus proving for the first time metabolic convergence of polyketide biosynthesis in eukaryotes. Traditional (1)H-(13)C NMR correlation spectroscopy has been successfully applied to estimate (13)C incorporation in biosynthetic experiments.     

Trace elements in marine waters by atomic absorption spectrophotometry

Trace elements of interest in sea water fall into two well-defined categories. Strontium, lithium, and rubidium are ideally suited to determination by atomic absorption spectrophotometry since minimal sample preparation is required and standard equipment may be utilized; standardization of techniques by which large batches of samples may be rapidly and accurately processed, is important. The transition elements are present in significantly lower concentrations and in complex, and largely unknown, chemical forms; pre-concentration is vital, Solvent extraction can also provide a crude differentiation between total and extractable fractions.     

Marine bioorganic chemistry as the base of marine biotechnology

Studies carried out at the Pacific Institute of Bioorganic Chemistry of the Far-Eastern Branch of the Russian Academy of Sciences and at other centers of structural investigation of marine organism metabolites were used as examples to consider some features of the biochemistry of marine natural products and the achievements of marine bioorganic chemistry, which open up ways to the development of new drugs and biological preparations.     

Trace metals in lignites and ashes of Greek power plants

In continuation, of an early study of trace metal /TM/ccontent of Greek lignites and power plant ashes, taken to assess mobilization of TM in Greece by the operation of power plants, new data are presented. Both power plant sites in Greece, i. e. /a/ Northern /Ptolemais, Kardia/, and /b/ Southern /Megalopolis/ have been examined for trace metal content in ashes and in locally used lignites. Instrumental neutron activation analysis /INAA/ was used to determine the content of about 30 minor and major elements. The uranium content of southern Greek lignites was found again to be exceptionally high. The new data are correlated with those of our previous investigation.     

Trace metal speciation in coastal and off-shore sediments from Ross Sea (Antarctica)

The information on total metal concentration in sediments is not sufficient to assess the metal behaviour in the environment, while speciation studies are more effective in estimating environmental impact of contaminated sediments. Concerning metal distribution in Antarctic marine sediments, several studies reported total or extractable (by means of a unique reagent) content, but only few publications dealt with metal speciation.This work presents the total content and speciation pattern of Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn in 12 cm sediment cores, sampled both in coastal and off-shore sites of the Ross Sea shelf area, within the framework of the Italian National Antarctic Programme (PNRA). The total content results of metals are comparable with the background values and the speciation highlights good environmental quality of the studied areas. Only Cd and Pb, in fact, are present in significative amount in non residual phases (acid-extractable and reducible, respectively).     

Trace metals species in sea-water-I: removal of trace metals from sea-water by a chelating resin

A significant fraction of the copper, lead, cadmium and zinc in sea-water exists in a form which is not retained by a chelating resin (Chelex-100) or extracted by ammonium pyrrolidinedithiocarbamate. Anodic stripping voltammetric results suggest that the major part of the unavailable trace metal is adsorbed on, or occluded in, organic or inorganic colloidal particles. An ionic equilibria computer program was used to predict the effect of various complexing agents on trace metal species in sea-water. Citric acid and amino-acids, with the exception of l-cysteine, were shown to be unimportant as complexing agents, and the ability of an EDTA-like ligand to complex Cu, Pb, Cd and Zn is controlled entirely by the concentrations of the ligand and of "labile" Fe(III) and Cr(III) in sea-water, since these two ions together will react quantitatively with EDTA. l-Cysteine, if present in sea-water, would also complex the trace metals.