SVIBOR - Project code: 1-08-089

MINISTRY OF SCIENCE AND TECHNOLOGY

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Project code: 1-08-089


TRANSPORT OF OSMOLYTES AND TOXIC METALS IN MARINE ORGANISMS


Main researcher: LUCU, ČEDOMIL (26622)


Assistants
Type of research: basic
Duration from: 01/01/91. to 12/31/93.
Papers on project (total): 42
Papers on project quoted in Current Contents: 10
Institution name: Institut "Ruđer Bošković", Zagreb (98)
Department/Institute: Center for Marine Research Rovinj
Address: Giordano Palliaga 5.
City: 52210 - Rovinj, Hrvatska
Communication
Phone: 385 (0)52 816 845
Phone: 385 (0)52 811-567
Fax: 385 (0)52 813-496
Phone: 385 (0)
E-mail: 385 (0)
Summary: Transport processes of the major inorganic osmolytes and toxic metals in the marine organisms were studied. The studies were undertaken by the gills - the very first communication and barrier between "internal milieu" of the organisms and their water environment which consists the natural constituents as well as potentially present pollutants. The underlying layer of the gill epithelium -rich with mitochondria is a selective barrier for ions and organic solutes. The gill permeability coefficients to the main osmolyte ions present in the blood and their environment showing the following permeability ratios P-Rb(K) : P-Na : P-Cl = 1.7 : 1.0 : 0.2. Electrical characterization of the isolated gill lamellae have shown the resistance of 30 Ohm cm2. Therefore, the gill epithelium have to be considered as a leaky epithelium.The presence of high-affinity enyzme Ca-ATPase and Na/Ca exchanger was for the first time described in the gills of shore crab Carcinus.The unidirectional influx of calcium significantly exceeded the efflux, indicating a net trans-gill influx of calcium.The calcium mobilization is of the utmost importance for the mineralization of the new carapace after crabs moulting.The effects of various concentrations of lanthanum on the cadmium and calcium influxes in isolated perfused gill epithelium were reported. The half-maximum inhibition of cadmium influxes effected by lanthanum occur at concentration of 1.4 micro mol/l. Cadmium transport across apical gill surface is discussed in terms of non-specific influx utilizing the non-specific Ca channels.The seasonal changes of the copper content were studied to establish patterns and to examine their fluctuations in a population of the shore crab Carcinus mediterraneus.A significant decrease of the copper content in the haemolymph and hepatopancreas and an increase of the copper space occur in the winter. These changes are closely related to the drop in the protein and copper haemolymph concentrations of the winter crab populations, when their activities and food intake are significantly decreased.Fluctuation of the natural and artificial radionuclides in Adriatic samples of seawater, plankton, pelagic and benthoic organisms and sediments were studied.The results allow to underline a representative picture of the Cs-137 concentrations in the seawater, organisms and sediment samples. The increased concentration of Cs-137 may be explained as a consequence of the Chernobyl catastrophy, by radioactive fall-out of river Po and by the stratospheric sources.

Keywords: Osmolyte transport, Heavy metals, Gills,Marine organisms, Natural and artificial radioactivity.

Research goals: The ultimate goal of the suggested studies are opening of the new frontiers in the transport mechanisms of the marine invertebrates. The challange of osmolarity is focused by studies on the cells of marine organisms.The topics of this proposal are highlights how comparative studies of the transport processes in aquatic animals can be aid of understanding of the mechanisms by which these organisms interact with and adapt to their environment.In addition, relative poor knowledge on the mechanisms of the toxic metal interaction with marine organisms will be broden with new facts. Moreover, radioecological studies in the marine environment are helpful for controlling of the base-line radionuclides level in the sea as well as to provide knowledge about the radionuclides biochemical cycle in the sea.The gill are "lung and kidney" of the aquatic organisms - selective communications with naturally present constituents in the seawater as well as with the pollutants which are intorduced in the marine environment. In contrast to the throughly investigated branchial ultrastructure and their transport functions, especially these explaining a role in energy-consuming osmoregulation processes, little is known about the energy providing processes. The natural and artificial radioactivity of some selected organisms, sediments and sea water will be studied.

COOPERATION - INSTITUTIONS


  1. Name of institution: Biologische Anstalt Helgoland, Hamburg, Njemačka
    Type of institution: State institute
    Type of cooperation: Joint project
    City: D-2000 - Hamburg, Njemačka
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Last update: 10/04/95
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