Comparative Analysis of Subcellular Distribution of Heavy Metals in Organs of the Bivalve Mollusks <Emphasis Type="Italic">Crenomytilus grayanus</Emphasis> and <Emphasis Type="Italic">Modiolus modiolus</Emphasis> in a Continuously Polluted Environment

The distribution of Zn, Fe, Ni, Cu, Mn, Cd, and Pb in subcellular fractions, and of Cd, Zn, and Cu in cytoplasm proteins of the kidney and digestive gland of the mussels Crenomytilus grayanus and Modiolus modiolus, sampled from contaminated and conditionally clean areas, was studied. It was found that, in a contaminated environment, the organs of mussels were more highly enriched with metals. It was shown that essential trace elements were accumulated mostly in the cytosol of organs of both molluscan species from contaminated areas, whereas in the background areas the trace elements were associated mostly with membrane structures in Gray's mussel, C. grayanus, and with the cytosol in M. modiolus, the northern horse mussel. The lead was bound mostly to membrane structures in organs of both mussel species at all stations. The method of gel chromatography enabled us to isolate metallothionein-like proteins from the kidney of the northern horse mussel sampled in contaminated areas, whereas their concentration in the kidney of Gray's mussels was lower than the limiting error of the method. It is supposed that in the kidney of Gray's mussel the synthesis of metallothionein-like proteins was quenched by the integrated effect of the accumulated metals.     

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.     

Comparative study of the bioaccumulation and elimination of trace metals (Cd,Pb, Zn,Mn and Fe) in the digestive gland,gills and muscle of bivalve Pinna nobilis during a field transplant experiment

The purpose of this study was to investigate the long-term bioaccumulation and elimination of Cd, Pb, Mn, Zn and Fe by Pinna nobilis tissues after their 90 day-transplantation period at Téboulba fishing harbor. During the transplantation period, the Cd, Pb, Mn, Zn and Fe concentrations in the different tissues of the mussels were measured before and after exposure period. Metal (Cd, Pb, Mn, Zn and Fe) accumulation in P. nobilis mussels varied depending on the analyzed tissue and the caging times. Notable differences in Cd, Pb, Mn, Zn and Fe accumulation patterns within the digestive gland, gills and muscle were found and may be due to the ability of each tissue to accumulate metals. During the depuration phase, the elimination of Cd, Pb, Mn, Zn and Fe depended on the target tissue and the metal speciation. Cd, Pb, Mn and Fe were eliminated rapidly from one organ and increased in other when compared to those of 90 day transplanted mussels. The increase of metal loads during the elimination phase is not clear and particularly what kind of processes is responsible for such response. However, it is reasonable to assume that metals increase is related to the existence of an accumulation/detoxification mechanism, which involves the transport of metals from an organ to another. The data obtained indicate that because of the significantly high quantities of Cd, Pb, Mn, Zn and Fe accumulated during the exposure phase, the transplanted mussels are suitable bioindicators for monitoring trace metals in marine ecosystem.     

Histopathology of the digestive gland of the bivalve mollusk Crenomytilus grayanus (Dunker, 1853) from southwestern Peter the Great Bay, Sea of Japan

The histomorphology of the digestive gland of the bivalve mollusk Crenomytilus grayanus from Sivuchya Bay, which is located in the southwest of Peter the Great Bay and subjected to the effect of polluted waters of Tumannaya River, was studied. Pathological changes of the digestive tubules, channels, and connective tissue of the gland were recorded in all the mussels studied. The epithelium of the tubules and channels was characteristic with erosive disturbances and by heavy vacuolization of digestive cells; connective tissue of the gland was specified by cells with lipofuscin (granulocytomes) and by foci of cells necrosis and lysis. Nervous fibers running in the gland were swollen in some mollusks. Strongly basophilic spherical formations, presumably one of the development stages of a parasitic plasmodium, were found in the granulocytomes and among vesicular cells of connective tissue of all the mussels. It was concluded that pathological changes in digestive gland of Gray’s mussel might be caused by chronic pollution of the bay and by parasitic invasion.     

Assessment of the state of the Japanese scallopMizuhopecten yessoensis in Alekseeva Bight (Peter the Great Bay, Sea of Japan) based on morphological and biochemical parameters

The results of an integrated examination of the state of the scallopMizuhopecten yessoensis in Alekseeva Bight (Peter the Great Bay, Sea of Japan) are presented. In mollusks of different ages, shell height was measured; in animals of commercial size (over 100 mm), some size and weight characteristics (annual increment of shell and adductor muscle and soft tissue weight) were determined. The morphology of the digestive gland and gills was studied. In the adductor muscle and digestive gland, the concentration of heavy metals (HMs) (Hg, Cu, Zn, Mn, Pb, Cd, Ni, Co, and Cr) was determined. In the digestive gland, metallothionein and reduced glutathione concentration was also determined, as was the activity of glutathione-dependent enzymes (glutathione peroxidase and glutathione reductase). In scallops collected outside Alekseeva Bight, the linear growth rate and adductor muscle weight were on average 1.3 and 1.7 times greater, respectively, than in those collected in the bight. In scallop organs, numerous histomorphological alterations were revealed: digestive cell vacuolization and hemocyte infiltration of the digestive gland, hyperplasia and vacuolization of the respiratory epithelium, and connective tissue hypertrophy in gill filaments. The biochemical parameters of scallops from Alekseeva Bight differed substantially from those of mollusks collected outside the bight. We conclude that one of the factors negatively affecting the state of theM. yessoensis population in Alekseeva Bight is the contamination of the bight with HMs, especially mercury. This is consistent with the results of chemical analysis of bottom sediments and tissues of two mytilid species,Modiolus kurilensis andCrenomytilus grayanus, specimens of which were collected in the bight together with the scallops [3].     

The digestive gland of the Southern Dumpling Squid (Euprymna tasmanica): structure and function

The cephalopod digestive gland plays an important role in the efficient assimilation of nutrients and therefore the fast growth of the animal. The histological and enzymatic structure of Euprymna tasmanica was studied and used in this experiment to determine the dynamics of the gland in response to feeding. The major roles of the digestive gland were secretion of digestive enzymes in spherical inclusions (boules) and excretion of metabolic wastes in brown body vacuoles. High levels of trypsin, chymotrypsin and α-amylase, low levels of α-glucosidase and negligible carboxypeptidase activity were produced by the gland. There was no evidence of secretion of digestive enzymes in other organs of the digestive tract. Within 60 min of a feeding event, the gland produced increasing numbers of boules to replace those lost from the stomach during the feeding event. Initially, small boules were seen in the digestive cells, they increased in size until they are released into the lumen of the gland where they are transported to the stomach. There was no evidence of an increase in activity of digestive enzymes following a feeding event, despite structural changes in the gland. However, there was large variation among individuals in the level of digestive enzyme activity. A negative correlation between boule and brown body vacuole density suggested that the large variation in enzyme activity may be due to the digestive gland alternating between enzyme production and excretion.     

Accumulation and excretion of aluminium and iron by the terrestrial snail Helix aspersa

1. The snail Helix aspersa was fed one 24 hr meal containing Al, Fe or both together in barley flour pellets. Accumulation and distribution within the digestive gland, kidney, crop and remaining soft tissues were examined over the subsequent 30 days using atomic absorption spectroscopy (A.A.S.).2. The digestive gland contained significantly (P < 0.05) elevated levels of Al and Fe for 8 and 12 days. The digestive gland is the major sink for both Al and Fe in Helix.3. The kidney rapidly accumulated Al and Fe but the increase was short-lived. The kidney may therefore be involved in the elimination of metal not incorporated into the digestive gland.4. Iron was absorbed by the crop but Al was not. This may indicate a route of uptake of Fe into the digestive gland not shared with Al.5. No obvious pattern of accumulation of Al and Fe were seen in the remaining soft tissues or the blood of Helix.6. Aluminium is present in the faeces for 12 days suggesting that Al is released relatively slowly.7. Presence of both Al and Fe in the feed induced a change in the pattern of accumulation in the digestive gland but not in the kidney, crop and remaining soft tissues.8. The distribution of Al is discussed in relation to the suggestion that Al follows the ferretin pathway during accumulation.     

Comparative study of the sterol composition of the digestive gland and the gonad of Sepia officinalis L. (mollusca,cephalopoda)

• 1.1. The sterol composition of the digestive gland and the gonad of Sepia officinalis L. was investigated by GC and GC-MS.
• 2.2. The same sterols were recognized in both organs, cholesterol being the major component of the sterol mixtures. However, quantitative differences appeared between the sterol composition of the digestive gland and the gonad.
• 3.3. The sterol mixtures of the digestive gland and the gonad of immature and mature females and males of various origins were compared. Quantitative changes in the sterol composition of the gonad were related to sexual maturity whereas the sterol composition of the digestive gland appeared linked to the diet.

     

Growth and shell morphology of three mytilidae (Bivalvia) species from the Sea of Japan

The growth and shell morphology of bivalve mollusks Crenomytilus grayanus, Mytilus coruscus, and Modiolus modiolus from the Sea of Japan are examined. The changes in body proportions and shell form in the ontogenesis of C. grayanus, M. coruscus, and M. modiolus are different even in the cases when the mussels develop in similar environmental conditions. Rapid growth shapes a well-streamlined and flat form of shell; slow growth leads to the formation of a massive and convex form. The parameters of the Bertalanffy growth curve for each species are calculated. The differences are discussed from the standpoint of functional morphology and spatial distribution patterns of mytilids in the coastal areas of the sea.     

The seasonal dynamics of diarrhetic shellfish poisoning toxins in the digestive gland of <Emphasis Type="Italic">Crenomytilus grayanus</Emphasis> (Dunker, 1853) analyzed by high-performance liquid chromatography with fluorometric detection

The seasonal dynamics of diarrhetic shellfish poisoning (DSP) toxins in the digestive gland of the mussel Crenomytilus grayanus (Dunker, 1853) from Peter the Great Bay in the Sea of Japan have been studied. Toxins in the form of 4-bromomethyl-7-methoxycoumarin derivatives have been analyzed using high-performance liquid chromatography (HPLC) with fluorometric detection. This method allows the determination of the quantitative and qualitative composition of individual toxins. All the C. grayanus samples contained DSP toxins, but their concentration varied substantially during the year. The highest concentration was recorded from the mussels collected in May; the lowest concentration was recorded in February. The toxins were represented predominantly by dinophysistoxin-2; in July-September and December, okadaic acid was detected. An assumption has been made about the relationship between the potential producers of DSP toxins in the waters of the Peter the Great Bay and the dynamics of these toxins in tissues of C. grayanus. The HPLC method, as an alternative to the enzyme-linked immunosorbent assay, was used to assess the quantitative and qualitative composition of DSP toxins in seafood for the first time in the Russian Federation. This method can be recommended for the routine monitoring of toxins conducted by the controlling organizations of the Russian Federal Service for Veterinary and Phytosanitary Surveillance.     

Trace metal content in the seagrass Cymodocea nodosa: Differential accumulation in plant organs

Differences in the accumulation of seven metallic elements, including micronutrients (Cu, Fe, Mn, Ni and Zn) and non-essential elements (Cd and Pb) among plant organs (leaves, roots and rhizomes) were examined in the seagrass Cymodocea nodosa. Samples were taken from two coastal bays (Catalonia, Western Mediterranean), with a total of nine sampling sites encompassing different levels of metal availability. Metal content was generally higher in uptake organs (leaves and roots) than in rhizomes. However, accumulation in leaves and roots varied between elements. While Cd, Mn and Zn preferentially accumulate in leaves, Fe and Pb accumulate in roots and Cu and Ni in both. There were common spatial (between sites) trends in Cd, Mn, Cu and Zn accumulation in the three organs. However, these spatial trends varied according to the organ considered in the case of Fe, Pb, and Ni. Therefore, assessment of within-plant variability is strongly recommended prior to the use of C. nodosa for biomonitoring purposes, at least for Fe, Pb, and Ni.     

Trace element composition of Ural licorice Glycyrrhiza uralensis Fisch. (Fabaceae Family)

The trace element composition of the subsurface (roots and rhizomes), overground (leaves and stems), and reproductive (bean valves) organs of Glycyrrhiza uralensis Fisch. was determined by synchrotron radiation X-ray fluorescence analysis (SRXFA). Concentrations of Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Y, Zr, Nb, Mo, Hg, Pb, Bi, Th, and U were measured. The data obtained were used to estimate the distribution of some elements in samples of various organs of licorice. Glycyrrhiza uralensis is an accumulator of Fe, Mn, Cu, and Co.     

Effects of Environmental Factors on Byssal Thread Formation in Some Members of the Family Mytilidae from the Sea of Japan

The ability to attach repeatedly to a substrate (glass, boulders, sand) in three common mussel species of the upper sublittoral zone of the Sea of Japan, Grayan's mussel Crenomytilus grayanus, the Korean mussel Mytilus coruscus, and northern horse mussel Modiolus modiolus, was studied under experimental conditions. It was found that during 120 h of the experiment C. grayanus and M. modiolus produced more byssal threads than M. coruscus. A decrease in the water temperature from 20 to 0°C slowed the rate of production of byssal threads down to full passivity in some experimental mollusks. This was more typical of M. coruscus and less typical of C. grayanus. Renewed threads differed in their length, thick, size of the adhesive plate, and strength. M. coruscus formed the shortest, thickest, and strongest threads with rather a large adhesive disk. The observed differences are discussed from the position of morphophysiological adaptations of species for colonization of different natural substrata under contrasting conditions of the upper sublittoral zone.     

Filamentous Fungi Associated with Bivalve Mollusks from Polluted Biotopes of Ussuriiskii Bay,Sea of Japan

We have studied for the first time the taxonomic composition of filamentous fungi associated with the bivalve mollusks Crenomytilus grayanus (Bunker, 1853) and Modiolus modiolus (Linnaeus, 1758), collected in polluted biotopes of Ussuriiskii Bay (Peter the Great Bay, Sea of Japan). One hundred fifty-five strains of higher fungi were isolated, and 35 species of filamentous fungi were identified. Out of these, 28 species were anamorphous fungi of the genera Aspergillus (12), Penicillium (10), Acremonium (1), Alternaria (1), Aureobasidium (1), and Cladosporium (3) (Deuteromycota), and 7 were species of the genera Chaetomium (6) and Myxotrichum (1) (Ascomycota). Twenty-four species of filamentous fungi were isolated from the internal organs of C. grayanus: 8 from the muscles, 8 from the hepatopancreas, 6 from the female gonads, 4 from the mantle, 3 from the kidneys and male gonads, and 1 from the gills. Twenty-one species of filamentous fungi were isolated from the internal organs of Modiolus modiolus: 10 from the muscles, 6 from the hepatopancreas, 5 from the female gonads, 3 from the kidneys, 3 from the mantle, and 1 from the gills. The bulk of the isolated species of the genera Aspergillus, Penicillium, Cladosporium, and Chaetomium were pathogenic and toxigenic fungi.     

Elemental alterations during the exposure of 1,2-dichloroethane (EDC), Disulfiram (DSF), and EDC-DSF to male Sprague-Dawley rats

Trace elements participate in the organ specific impact of 1,2-dichloroethane (EDC) and Disulfiram (tetraethylthiuram disulfide; Antabuse (DSF)) administered singly or together, on male Sprague-Dawley rats exposed by diet (AIN-76) to DSF (0 and 0.15% for 10 d before and during exposure to EDC) and by inhalation to EDC (0,153, 304, 455 ppm (v/v); 7 h/d for 5 d/wk for 30 exposure days). Kidney, liver, spleen, and testes at exposure d 30 as well as progressive urine samples were examined for elemental content by simultaneous inductively coupled plasma atomic emission spectroscopy. Each compound singly or together produced EDC dose related (r≥0.8) changes in metal content in organs relative to controls. There were increases induced by EDC alone for P and Sr in the liver and decreases for Fe, Mg, and P in the spleen. EDC in DSF-exposed animals caused increases in Ca, Cu, Fe, Mn, and S and a decrease in K in the liver; increases in Ca, Cu, Fe, Mn, Mo, P, and S and a decrease of Zn in the testes; an increase in Fe and a decrease in K in the spleen; and an increase of P in the kidney. DSF alone increased Cu in the liver but decreased it in the testes and kidney; Pb was increased in the liver and kidney and Zn in the liver, spleen, and kidney; Al and Si were increased also in the liver, S in the spleen, and K in the kidney; Mn and Na were decreased in the kidney. The organs showing histopathology (the liver and testes) both showed increases in Ca, Cu, Fe, Mn, and S. Metals in urine characterized a “shock” impact of the initial exposure by initial excretion of Na and retention of most other elements. After steady state (>12 d), EDC alone caused increases for Sr and Zn; for EDC-DSF, EDC also decreased Na in addition to the changes elicited by DSF alone (increases in S and Zn and a decrease for Cu). The results were interpreted from the perspective of the effects of metals on the glutathione detoxicative pathway, the concentration of free diethyldithiocarbamate in urine, and an interaction with bone. Mechanisms of action of EDC, DSF, and EDC-DSF must include consideration of trace elements in addition to organic intermediates, metabolites, and enzymes.     

The effects of zinc oxide nanoparticles on the metallome in freshwater mussels

The use of zinc oxide nanoparticles (nanoZnO) as sunscreens has raised concerns about their safety and release in the aquatic environment through swimming activities and within municipally treated wastewaters. This study's purpose was to examine the effects of nanoZnO on the elemental composition (metallome) in exposed freshwater mussels, Elliptio complanata. Mussels were exposed for 21 days to an environmentally realistic (low) concentration (2 μg/L) of nanoZnO and zinc chloride. The mussels were also exposed to a physically and chemically treated municipal effluent (ME), both alone and in the presence of both forms of Zn. The metallome profile was characterized by the following 15 elements in gills, digestive gland and gonad tissues: Ag, Al, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Se, V and Zn. The levels of metallothioneins (MT) and lipid peroxidation (LPO) in the digestive gland were also measured as biomarkers of toxic effects. The data revealed that exposure to nanoZnO increased the total levels of Zn, MT and LPO in the digestive gland. Discriminate function analysis revealed that the digestive gland responded the most to exposure to either nanoZnO or Zn^2 +. For nanoZnO, the observed changes in Al, As and Mo in the digestive gland offered the best discrimination from dissolved Zn^2 +. Co-exposure of nanoZnO with the ME changed the metallome profile closer to dissolved Zn^2 +, suggesting a common interaction site within the ME. This was observed in changes in Ni, Cu, Se and Zn in the digestive gland of exposed mussels. Canonical analysis of essential and non-essential elements revealed that exposure to nanoZnO increased the relationships between LPO and the sum of essential elements in the digestive gland. Conversely, exposure to dissolved Zn^2 + and the ME decreased the relationship between the sum of non-essential elements and LPO and MT. In conclusion, the use of a “metallomic” approach was used to discriminate changes following exposure to nanoZnO and dissolved Zn in freshwater mussels and provided insights into the interaction of forms of Zn in ME towards mussels.     

Cadmium-Induced Oxidative Stress in the Bivalve Mollusk <Emphasis Type="Italic">Modiolus modiolus</Emphasis>

Cadmium-induced oxidative stress in the bivalve Modiolus modiolus is studied from the standpoint of the universality of the mechanism of free-radical oxidation. The kinetics of cadmium accumulation by the bivalve was revealed in a laboratory experiment. The gills accumulated higher Cd levels than the digestive gland. In the process of cadmium accumulation, there was an increase in lipid peroxidation products (malondialdehyde and lipofuscin) and a reduction in the total oxiradical scavenging capacity (TOSC). Cadmium induces oxidative stress in molluscan tissues through damage to the antioxidation system. Thus, TOSC can provide a useful biochemical indicator of early pathological changes in the cell or the organism, as well as of the environmental effects of heavy metal pollution.     

Metals in some dominant vascular plants, mosses, lichens, algae, and the biological soil crust in various types of terrestrial tundra, SW Spitsbergen, Norway

Arctic environments are commonly considered to be relatively pristine because of minimal local human activity. However, these areas receive air pollution from lower latitude regions. Our goal was to determine concentrations of metals (Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn) in dominant species of vascular plants, mosses, lichens, algae, and in the biological soil crust (BSC), and topsoil (0–3 cm) from various types of tundra in the southwestern part of Spitsbergen, Norway. Results indicate that mosses are more efficient bioaccumulators of Cd, Co, Cr, Cu, Fe, Mn, and Zn than lichens. The highest levels of Co, Cr, Cu, Fe, Hg, Mn, Ni, and Pb were found in the BSC, and the moss species Racomitrium lanuginosum, Sanionia uncinata, and Straminergon stramineum from the polygonal tundra, initial cyanobacteria-moss wet tundra, snow bed cyanobacteria-moss tundra, and flow water moss tundra alimented by melting ice or snow. The observed higher concentrations of Cu and lower concentrations of Hg in mosses, lichens, and vascular plants compared with values observed 20 years earlier were apparently associated with changes in the atmospheric deposition of contaminants over Spitsbergen due to changes in the long-distance transport of anthropogenic emissions from industrialized areas. Prasiola crispa and Salix polaris may be useful bioindicators of Cd and Zn, and the BSC, R. lanuginosum, S. uncinata, and S. stramineum as bioindicators of Co, Cr, Cu, Fe, Hg, Mn, Ni, and Pb. These results may be extrapolated across other areas of Spitsbergen with similar climates.     

The growth and lifespan of the mussel Crenomytilus grayanus (Bivalvia: Mytilidae) in the Tatar Strait (Sea of Japan) in connection with the conditions of life at the northern border of the species range

The study of materials that were collected by trawling and diving in the Tatar Strait (Sea of Japan) in 2010 showed that the commercial bivalve Crenomytilus grayanus is distributed northward along the continental coast of the Khabarovsk region to Mosolov Bay (51°14.308?? N, 140°42.358?? E). Mussel druses and single mussels were found at depths of 3?C32 m in bays, along the open sea coast on rocks, boulders, and in other biotopes characteristic of this species. The growth rate of C. grayanus in the Tatar Strait varied depending on the habitat conditions and was markedly lower than in the warmer waters of Peter the Great Bay, where at similar depths this species reaches its legal size 5?C8 years earlier. The lifespan of C. grayanus in the Tatar Strait is 126 years, a value comparable with the lifespan of this species in more southern areas.     

Morphofunctional changes of the digestive gland in the bivalve mollusk Crenomytilus grayanus (Dunker, 1853) in normal conditions and after parasitic invasion by trematodes

Specifics of the digestive cycle were studied in normal individuals of Gray’s mussel Crenomytilus grayanus and in those infested by trematodes from an unpolluted area of the sublittoral zone of Peter the Great Bay in May (during the day), June, July, and August. Four types of tubules corresponding to four phases of the digestive cycle were identified, and three varieties of destructing tubules were distinguished. It was shown that normally phases of absorption and digestion prevailed in the digestive gland. The portion of absorptive tubules (type II) was 95% in spring and 79% in summer. The total portion of destructing and restoring tubules (types III and IV) did not exceed 10% in spring and 20% in summer, and portion of tubules at the initial condition (type I) was 4% in spring and 2% in summer. During the day, insignificant variations in the ratio of different type tubules were recorded. It was revealed that, normally, granulocytomes were formed during utilization of necrotic tubules. Parasitic invasion of trematodes entailed swelling of the gland and a change in the proportion of tubules: the number of absorptive tubules decreased to 20%, the number of destructing and restoring tubules increased up to 60% and 12%, respectively.