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  • 1985-1989  (6)
  • 1980-1984  (7)
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Year
  • 1
    Electronic Resource
    Electronic Resource
    Tissue and subcellular distribution of 252Cf and 241Am in the seastar Marthasterias glacialis (1983)
    Springer
    Marine biology 75 (1983), S. 253-259 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Seastars, which are known to accumulate transuranium nuclides to relatively high levels, were used in laboratory radiotracer experiments (April–May, 1982) designed to determine the subcellular distribution of tissue-incorporated californium-252 and americium-241. Mediterranean asteroids (Marthasterias glacialis), collected in April 1982 and fed prey contaminated with 252Cf and 241Am, accumulated and retained large fractions of these radionuclides (252Cf, 91 to 98%; 241Am, 82 to 88%) in their pyloric caeca, the glandular complex involved with digestive and food storage processes. Differential centrifugation demonstrated an association of 252Cf and 241Am with the lysosome-mitochondrial fraction of plyoric caeca cells. Partial separation of lysosomes and mitochondria by isopycnic gradient centrifugation suggests a somewhat different subcellular fractionation of the two transuranics; 252Cf is associated primarily with the mitochondria, whereas 241Am is accumulated in both lysosomes and mitochondria. From comparison with analogous studies in mammalian systems, it is hypothesized that the long biological half-lives reported for ingested transuranics in seastars result in large part from the radionuclide association with mitochondria in the pyloric caeca.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00406010
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  • 2
    Electronic Resource
    Electronic Resource
    Interactions of marine plankton with transuranic elements (1983)
    Springer
    Marine biology 75 (1983), S. 261-268 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In a series of laboratory experiments, the biokinetics of 241Am, an important transuranium element, was studied in Meganyctiphanes norvegica, a euphausiid common in the northwestern Mediterranean. The euphausiids accumulated Am from water by passive adsorption onto exoskeletons, achieving wet weight concentration factors on the order of 102 after 1 wk exposure; concentration factors varied inversely with the size of the euphausiids and linearly with their surface area:wet weight ratios. Essentially all (96±10%) of the Am taken up from water was associated with the exoskeleton, so that negligible Am was retained by the euphausiids after molting. The retention half-time of Am in molts was 2.9 d. Euphausiids could also concentrate Am from feeding suspensions by ingesting Am-labelled diatom cells, although there was negligible Am assimilation (3±2% after 4 d feeding); after passage through the gut, virtually all (≃99%) of the ingested Am was defecated within 1 wk. The retention half-time of Am in fecal pellets was 41 and 51 d at 13° and 5°C, respectively. In oceanic waters, where the preponderance of 241Am is in the dissolved phase, uptake of Am from water by euphausiids would be the dominant route of bioaccumulation. The results underscore the importance of sinking biogenic debris from zooplankters in mediating the vertical transport of Am in the sea. Given their retention half-times for 241Am and their rapid sinking rates, fecal pellets and discarded molts have the potential to deliver most of their Am to the sediments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00406011
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  • 3
    Electronic Resource
    Electronic Resource
    Assimilation, inter-organ transfer and excretion of americium in two teleost fish (1983)
    Springer
    Marine biology 77 (1983), S. 59-66 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Radiotracer experiments were performed (February–April, 1982) to study the assimilation and metabolism of the transuranium nuclide americium-241 in the marine teleosts Serranus scriba (Linnaeus, 1758) and Scorpaena notata Rafinesque, 1810, caught off the Monaco coast. Fish fed with 241Am-labelled food showed that assimilation of this radionuclide takes place through the gastrointestinal walls and that the small fraction accumulated is incorporated mainly in the skin, muscle and skeleton. Gut-transfer coefficients were similar in both species and averaged 0.7% (range 0.1 to 1.7%) of the ingested activity. The calculated biological half-lives for loss of the absorbed fraction ranged between 49 and 61 d for Serranus scriba and 12 and 117 d for Scorpaena notata. Results from an intramuscular injection experiment indicated that 241Am was retained mainly in the liver, skin and skeleton; the fraction accumulated by muscle was very low. Liver displayed a relatively short biological half-time for 241Am loss of roughly 24 d. Routes of 241Am excretion from the teleosts appear to be through the kidneys, gills and feces with bile serving as a possible excretion route from the liver. From the limited amount of published information available for comparison, experimental evidence is presented which suggests that 241Am taken up via the food chain is more biologically available to marine fish than is plutonium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393210
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  • 4
    Electronic Resource
    Electronic Resource
    Intracellular localization and binding of technetium-95m in the seastar Marthasterias glacialis (1985)
    Springer
    Marine biology 85 (1985), S. 43-50 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The subcellular distribution of technetium was studied using the seastar Marthasterias glacialis which had previously ingested prey labelled with 95mTc either as pertechnetate (VII) or in the reduced state (IV). The majority of the Tc [98% (IV) and 96% (VII)] was taken up and retained in the pyloric caeca, the gland responsible for digestive and food storage processes. Differential centrifugation and separation techniques have demonstrated that, at the subcellular level, technetium in the pyloric caeca was largely associated with the lysosomes. 95mTc (IV) was distributed between the lysosomes and the soluble fraction to roughly the same degree, whereas pertechnetate was more strongly associated with the lysosomal fraction. Chromatography of the cytosol by gel filtration indicated the presence of two distinct protein compounds which were responsible for binding virtually all of the technetium in the soluble fraction. Technetium had a greater relative affinity for the low molecular weight compound, more so for Tc (VII) than for Tc (IV). This anionic protein had an apparent molecular weight of approximately 10 000, and thus may play a role in metal detoxification mechanisms at the cellular level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00396413
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  • 5
    Electronic Resource
    Electronic Resource
    Organochlorine levels in edible marine organisms from Kuwaiti coastal waters (1987)
    Springer
    Bulletin of environmental contamination and toxicology 38 (1987), S. 266-270 
    Details
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01606672
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  • 6
    Electronic Resource
    Electronic Resource
    Non-steady-state biological removal of atmospheric particles from Mediterranean surface waters (1989)
    [s.l.] : Nature Publishing Group
    Nature 340 (1989), S. 131-134 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Sampling and analysis of total (wet + dry) atmospheric depo-sition samples for aluminium, an indicator of aluminosilicate minerals, have been described elsewhere1. Samples have been collected with a hemispheric plastic collector (of area 0.1 m2) at Capo Cavallo (42° 31' N, 8° 40' E), ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/340131a0
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  • 7
    Electronic Resource
    Electronic Resource
    Uptake of 55Fe from contaminated sediments by the polychaete Nereis diversicolor (1980)
    Springer
    Marine biology 56 (1980), S. 277-280 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The polychaete Nereis diversicolor O. F. Müller was exposed to marine sediments which had been contaminated with 55Fe either through the testing of nuclear devices or by the release of liquid waste effluent from a nuclear fuel reprocessing plant. The amount of 55Fe taken up reached a concentration in the worms about 6% of the concentration in both types of sediment. Bioavailability of 55Fe was shown to depend on its concentration in sediment and not on sediment type, stable iron concentration, or the source of contamination. N. diversicolor may not extract from sediment the same fraction of 55Fe as does 0.1N HCl and caution should be exercised in using such measurements to represent the bioavailable fraction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386865
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  • 8
    Electronic Resource
    Electronic Resource
    Vanadium transfer in the mussel Mytilus galloprovincialis (1980)
    Springer
    Marine biology 56 (1980), S. 281-293 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Radiotracers were used to study processes controlling the accumulation and elimination of vanadium in the Mediterranean mussel Mytilus galloprovincialis. Vanadium uptake rates varied inversely with both salinity and vanadium concentration in water, but were independent of temperature. After a 3 wk exposure to 48V, the highest concentration factors were found in the byssus (≈1900) with much lower values computed for shell (≈ 70) and soft tissues (≈5). More than 90% of the total 48V accumulated was fixed to shell, suggesting that uptake is primarily a result of surface sorption processes. Much of the vanadium in shell was firmly bound to the periostracum and was not easily removed by acid leaching. Food-chain experiments indicated that the assimilation coefficient for ingested vanadium is low (≈7%) and that the assimilated fraction is rapidly excreted from the mussel. These findings coupled with knowledge of in situ and experimentally-derived vanadium concentration-factors have allowed a preliminary assessment of the relative importance of the food and water pathways in the contamination of mussels under conditions of acute and chronic exposure. Contaminated mussels transferred to clean sea water lost 48V at rates that depended upon temperature but were largely unaffected by either salinity or by vanadium levels in mussel tissues. Total vanadium depuration was slow and was governed by loss from a slowly-exchanging compartment with a characteristic half-time of about 100 d. Individual mussel tissues were analyzed for stable vanadium and the possibility of using these tissues, particularly the byssus, as bioindicators of ambient vanadium levels in the marine environment is also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386866
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  • 9
    Electronic Resource
    Electronic Resource
    Comparative study of vanadium biokinetics in three species of echinoderms (1982)
    Springer
    Marine biology 67 (1982), S. 127-134 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Vanadium-48 (as vanadate) was used to study the uptake, tissue distribution, depuration and food-chain transfer of vanadium through 3 species of echinoderms: the seastar Marthasterias glacialis L., the sea urchin Paracentrotus lividus Lmk. and the holothurian Holothuria forskali D.Ch.; all were collected from the littoral zone near Monaco. Uptake by all species was relativelyslow; after 3 wk exposure, isotopic equilibrium had not been reached and whole-body concentration factors ranged from 5 and 7 in the holothurian and sea urchin, respectively, to 18 in the seastar. Sixty-three to 77% of the incorporated radiotracer was associated with the body wall or test, suggesting surface sorption as the principal mechanism governing uptake from water. Stable vanadium measurements confirmed the preponderance of this element in the external hard parts of the echinoderms; however, concentration factors based on stable vanadium levels were significantly higher than those measured experimentally. Subsequent vanadium depuration rates were also species-dependent, with biological half-times for loss ranging from approximately 50 d in the sea urchin and holothurian to 123 d in the seastar. Food-chain transfer experiments indicated that seastars can assimilate and retain a large fraction of the vanadium ingested with food whereas sea urchins appear to lack this capability. The relative importance of the water and food input pathway in achieving vanadium levels in echinoderms is discussed in light of results of 48V distribution in experimental individuals and stable vanadium distribution in samples from the natural environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00401278
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  • 10
    Electronic Resource
    Electronic Resource
    Long-Term observations on the moulting frequency of the shrimp Lysmata seticaudata (1980)
    Springer
    Marine biology 59 (1980), S. 219-223 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of body-size and temperature on moulting frequency of the shrimp Lysmata seticaudata Risso were examined under controlled laboratory conditions. Shrimp ranging in weight from approximately 0.4 to 1.14 g and maintained at 17°C exhibited intermoult periods of similar duration (≈20 d). On the other hand, small individuals (0.23 g) held at the same temperature moulted on the average every 14.5 d. Over a temperature range from 8° to 20°C mean intermoult periods were inversely and linearly related to temperature; an increase of 1 C0 resulted in a decrease in the intermoult period of approximately 1.5 d. Although temperature acted to regulate the intermoult period of each shrimp in increments of whole days, it had little effect on the time of moulting within any 24 h period, since moulting occurred more than 93% of the time between 18.00 and 08.00 hrs. The night-time moulting pattern also tended to be most pronounced at lower temperatures (8° and 13°C) and in larger individuals. Possible factors controlling this phenomenon and its occurrence in other crustacean species are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00404744
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