Organs Of Mussels Research Articles

Changes in the Microelement Composition in Organs and Tissues of the Bivalve Crenomytilus grayanus Acclimatized in a Biotope with Long-Term Heavy Metal Contamination

This paper deals with changes in the Fe, Zn, Cu, Cd, Mn, Pb, and Ni concentration in the muscle, gonad, mantle, gills, digestive gland, and kidneys of Gray mussels transplanted from two sites differing in the extent of metal contamination to a biotope with the impact from anthropogenic conditions in the course of their acclimatization. The rate of metal accumulation depended on the initial element concentration in the mussel organs. An abrupt change in the metal concentration in the environment was followed by a disturbance in the microelement balance in some organs. The microelement metabolism was shown to depend on mussel preadaptation to a changeable environment.

Heavy Metal Accumulation and Distribution in Organs of the Mussel Crenomytilus grayanus from Upwelling Areas of the Sea of Okhotsk and the Sea of Japan

The subcellular and cytosolic distribution of Zn, Fe, Ni, Cu, Mn, Cd, and Pb in the digestive gland and kidney of the mussel Crenomytilus grayanus from upwelling areas of the Sea of Okhotsk and the Sea of Japan was studied. Cd, Zn, Pb, and Ni have accumulated in the kidneys of mussels from these areas. When the concentrations of both essential and toxic metals in the mussel organs had increased significantly, their redistribution into the cytosol took place. Gel chromatography of cytosolic proteins in the kidneys of mussels sampled in the area with a strong stationary upwelling revealed metallothioneins. This is uncommon for bivalve mollusks from unpolluted areas. High molecular weight proteins act as preliminary ligands for Cd.

Analysis of the importance of lipid breakdown for elimination of okadaic acid (diarrhetic shellfish toxin) in mussels, Mytilus edulis: results from a field study and a laboratory experiment

Okadaic acid (OA) is a lipophilic phycotoxin, which accumulates in the digestive organs of mussels and may cause diarrhetic shellfish poisoning (DSP) in humans. Depuration of toxic mussels is a potential option for the shellfish industry to increase the availability of marketable mussels. To develop cost-effective depuration methods for DSP toxins, knowledge about the environmental conditions and physiological processes regulating the rate of depuration is essential. In this paper, the importance of lipid breakdown for elimination of OA in mussels was investigated by performing a field study and a manipulative laboratory experiment. First, total lipid content and concurrent concentration of OA in the digestive glands of farmed blue mussels, Mytilus edulis, was analysed on a monthly basis from January to June 2000. A significant positive correlation between levels of OA and lipid content was observed between January and March, when lipid levels were showing a decreasing trend. This supported a previously proposed model that breakdown of lipid stores may affect the release and elimination of this lipophilic toxin. To test this causal model, a laboratory experiment was performed. Mussels containing OA were exposed to experimental treatments (increased seawater temperature and/or food limitation) for 24 days in order to increase the energy requirements and need to use lipids as an energy source. It was predicted that mussels exposed to these treatments would have a faster elimination rate of OA compared to feeding mussels kept in ambient seawater temperature. The results showed that lipid content was significantly reduced in mussels exposed to an increased water temperature (24 °C) compared to ambient temperature (18 °C). The amount of lipids was not affected by food limitation. Although lipid content was reduced in 24 °C, the rate of depuration of OA was not faster for mussels in this treatment and no correlation was detected between lipid content and OA. Depuration rates were very similar for all treatments and followed an exponential decrease relationship ( t 1/2=8 days). Thus, the proposed model that lipid breakdown affects the mechanism of elimination of OA was not supported. Nevertheless, the observed rates of depuration provide useful information and a potential predictive tool for large-scale depuration methods of mussels. The difficulties to influence the rate of depuration of this toxin by changing the environmental conditions suggest that processes, insensitive to short-term manipulation of the external environment, regulate depuration of OA.

Comparison between isolation protocols commonly used for the purification of mollusc metallothioneins

Two centrifugation methods (at 30 000 and 100 000 g) combined with two isolation procedures (heat denaturation and solvent precipitation) were tested to check if their use introduced significant differences in the quantification of metals (Cd, Cu, Zn) and metallothioneins in blue mussel organs (gills and digestive gland). No contaminating compounds originating from the lowest centrifugation speed were likely to interfere with quantitative measurements of metal, protein and metallothionein. As isolation treatments act on specific properties of proteins in general and metallothionein isoforms in particular they cannot be used interchangeably. Therefore, any comparisons of MT amounts in bivalve tissues with data from the literature have to take into account the isolation procedure. Similar results were obtained with three other molluscs, Crassostrea gigas, Bathymodiolus thermophilus (hydrothermal mussel), and Corbicula fluminea (estuarine bivalve).

The contribution of metal/shell-weight index in target-tissues to metal body burden in sentinel marine molluscs. 2. Mytilus galloprovincialis

The tissue distribution of Zn in mussels collected from a Zn-polluted site and the changes in the pattern of distribution for Zn and Cu in response to experimental exposures to Cu, Zn and Cd, as well as the tissue distribution of Cd have been studied. The organs of mussels were accurately separated avoiding mixtures except the kidney area that was included within the remainder tissues. Mussels exposed to intermediate dose (ID)-Cd showed the highest Cd burden first in gills and then more or less equally distributed between the various tissues examined with a dominance of the digestive gland. Mussels exposed to high dose (HD)-Cd, showed Cd equally distributed through all the organs at both exposure times. Below 0.8 μg Cd/l seawater, the gills of Zn-polluted mussels were able to either protect against Cd entry or mobilise uptaken Cd towards other tissues. On the other hand, Zn- and Cu-burdens did not rise in gill tissue, although in depurating mussels Zn-levels were higher than in any other exposure group. Similar conclusions were obtained for the digestive gland. However, the accumulative capacity of the digestive gland tissue for Cd was not exhausted and Cu burdens were depressed on exposure to Cd. Interactions between metals in the various organs studied could be explained by redistribution of haemocytes or brown cells and by enhanced release of metal-bearing digestive lysosomes in response to metal exposure. It is suggested that (a) the pattern of metal accumulation and tissue distribution as well as a part of the interactions between Cu, Zn and Cd cannot be explained solely by the availability of metallothioneins in specific organs; and (b) the specific cell type in which these ligands occur as well as the relative abundance and distribution of these cells are relevant factors controlling metal burdens in organs of mussels. Therefore, in addition to the chemical and the biochemical approaches, investigations on tissue sections are required to better understand these phenomena. Meanwhile, the digestive gland of mussels could be used as the target organ to monitor metal pollution, including essential and non-essential metals, on the basis of metal/shell-weight indices.

Distribution of natural radionuclide40K in biotic and abiotic components of the Cauvery river system, Tiruchirapalli, India

Abiotic components like water and sediment, and biotic components such as mussels, fish and grass collected from Cauvery river at Tiruchirapalli were analysed for40K activity. The highest level of40K activity was found in the sediment (342 mBq g-1 dry weight) and the lowest activity was found in water (2·209 mBq ml−1). In the freshwater musselParreysia favidens (Benson)40K activity was estimated in the total soft tissues and shells of mussels belonging to three different size groups. In all the size groups40K activity was two times higher in shells (68–39 mBq g-1 fresh weight) than in the total soft tissues (25–17 mBq g-1 fresh weight). The results indicate that the younger mussels accumulated more40K than the older ones. The ability of internal organs of mussels belonging to group III to accumulate40K was in the following order: gills > digestive gland > foot > mantle. The values ranged from 47 to 18 mBq g−1 fresh weight in the various organs. Concentration of40K in the mussel was distinctly higher than in the grassEchinochloa colonum (J Koenig) (95 mBq g−1 fresh weight), and the concentration of40K in the bone of the fishCirrhina cirrhosa (Bloch) (126 mBq g−1 fresh weight) was higher than to that of muscle (113 mBq g−1 fresh weight)

Bioaccumulation of nickel in the organs of the freshwater fish, [formula omitted], and the freshwater mussel, [formula omitted], under lethal and sublethal nickel stress

Nickel concentration, measured by Atomic Absorption Spectrophotometry (AAS), increased significantly in the gill, kidney, liver, brain and white muscle of the freshwater fish, C. carpio , and in the ctenidium, hepatopancreas, mantle, adductor muscle and foot of the freshwater mussel, L. marginalis , at 1, 2, 3 and 4 days on exposure to lethal and at 1, 5, 10 and 15 days on exposure to sublethal concentrations of nickel. The amount of nickel accumulated was higher in the organs of animals exposed to lethal but, it increased over time of exposure in both the concentrations. Further, the nickel accumulated was significantly higher in the organs of mussel than fish. The degree of accumulation also differed in different organs of the fish and mussel, the significance of which is discussed.

Bioaccumulation of metals by bivalves from the limski kanal (North Adriatic Sea) IV. Zinc distribution between mytilus galloprovincialis, ostrea edulis and ambient water

From June 1979 to June 1980 the accumulation of zinc by the mussel Mytilus galloprovincialis and the oyster Ostrea edulis, from the Limski Kanal on the west coast of Istria, SR Croatia, Yugoslavia, was determined. The distribution of zinc within tissues and organs of mussels and oysters of the same length was related to the zinc concentration in the ambient water. Three physico-chemical forms of zinc can be distinguished in seawater: “ionic” dissolved (Zn electro-chemically determined at the natural pH of seawater); “total” dissolved (Zn determined after sample acidification to pH 2); and particulate Zn (bound to suspended particles with a diameter 0.45 μm). The zinc content of different tissues and organs of both species increased significantly with an increase in their condition factors. Zinc concentration decreased significantly in all body parts of the oyster, but, in the mussel, only the foot was affected. Zinc concentrations in organs that are directly involved in the reproductive cycle showed a seasonal variation. The zinc concentration in the mantle of mussels was significantly and positively correlated with the “ionic” and “total” dissolved zinc content of water. Elevated amounts of particulate material suspended in the ambient water increase the filtration rate, which resulted in an accelerated accumulation of zinc by mussels, but not by oysters. Differences in zinc concentration between samples suggest that the dynamics of accumulation and loss may differ during the year; first, mainly as a consequence of the reproductive cycle in bivalves and the concentration of stimulants for filtration in the surrounding water, and second, by coastal input of Zn and by the amount of metal remobilized from the sediment.

Polonium-210 in mussels and its implications for environmental alpha-autoradiography

Alpha-autoradiographic and radiochemical studies of the distributions of transuranic nuclides in the tissues and organs of mussels collected from the vicinity of the British Nuclear Fuels plc reprocessing plant at Sellafield, Cumbria, England, appeared to require assessment also of baseline alpha-activities of natural 210 Po levels. Results for the latter were found to be in excess of the anthropogenic activities of Pu and Am isotopes. To ensure that the levels of 210 Po in Cumbrian mussels were not artificially enhanced by local discharges and in the absence of published data, mussels from remote British and French coastal sites were also analyzed. General similarities in 210Po concentrations (111 to 459 Bq kg −1 dry) found in mussels soft parts suggest that the 210Po levels in the Ravenglass mussels (279 Bq kg −1) are natural and largely unsupported by 210Pb; however these levels are as much as four times greater than the present day 239+240Pu concentrations in the same samples. As the transuranic nuclide content of Cumbrian mussels produces a major component of the local critical group radiation exposure from the Sellafield discharges, this finding places in some perspective the significance of the baseline natural radionuclide concentrations in generating total exposure of the public. More specifically, these findings severely limit the usefulness of alpha-autoradiographic studies for transuranic nuclides performed on such samples. Because of the recently lower concentrations of alpha-emitting transuranic nuclides (mainly 238Pu, 239+240Pu and 241Am) in the Ravenglass environment, natural 210Po is now a major contributor to alpha-track distributions in autoradiographic studies.

Heavy metals in animals of Lake Balaton

Hg, Cd, Cu, Pb, Zn, Fe and Mn concentrations were measured in Chironomidae larvae, Crustacea plankton, as well as in various organs of mussels and fishes collected from the open water area of Lake Balaton. The values were comparatively low. However, there were significant differences in the metal concentrations of species and tissue. Most Cd was found in the gill of Unio pictorum L., most Pb, Zn and Mn in the gill of Anodonta cygnea L., most Cu in Crustacea plankton and in the liver of Abramis brama L., and most Hg and Fe in Chironomidae larvae. Low concentrations occurred in fishes, the lowest in the flesh of Stizostedion lucioperca L. Accumulation of metals in organs as compared with their concentration in the lake water was in the range of 3.4 × 10 2−2.6 × 10 3 for Hg; 7.0 × 10 2−6.8 × 10 3 for Cd; 3.3 × 10 2−9.7 × 10 3 for Cu; 6.9 × 10 2−8.1 × 10 3 for Zn; 1.5 × 10 3−2.4 × 10 4 for Pb; 3.5 × 10 2−3.1 × 10 4 for Fe; and 5.0 × 10 1−3.5 × 10 5 for Mn.