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Galectins are a member of the β-galactoside binding protein family, which play a pivotal role in the immune defense of vertebrates as a pattern recognition receptor and occupy an important position in the innate immune system of invertebrates. The study of galectins in aquatic organisms has only recently emerged. Galectins in aquatic animals exhibit agglutination activity toward bacteria, inhibit bacterial growth, and enhance phagocytosis of immune cells. Additionally, some galectins contribute to the antiviral immune defenses of aquatic animals. This review aims to review recent advancements in the antimicrobial mechanisms, molecular structures, and evolution of galectins from fish, mollusks, and crustaceans. The antimicrobial galectins, as crucial components in the innate immune defense, pave new avenues for developing innovative disease control strategies in aquaculture.

The concentration of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn were analyzed in the edible part of several species of fish, crustaceans, molluscs and echinoderms collected in sensitive areas of the Tuscany coast (northern Italy). The concentration of As (0.39-78.1 μg g -1 ) and Hg (0.01-1.56 μg g -1 ) resulted in most cases higher than reference thresholds. Target hazard quotient (THQ) and lifetime cancer risk (TR) indexes were calculated to assess cancer and non-cancer risk due to oral exposure; the highest THQ values referred to As and Hg, with values ≥ 1 in 39% and 48% of cases, respectively. Total target hazard quotients (TTHQ) values suggested that the local population could experience adverse health effects due to consumption of local seafood, mainly of demersal and benthic species. Cancer risk was mainly associated with As exposure, and with Cd intake, especially through molluscs consumption. The NMDS model highlighted species specific bioaccumulation processes and specific sensitivity of species to different bioavailable heavy metals. Specifically, Mullus spp. and Scorpaena porcus preferentially accumulate Hg and Cr, Octopus vulgaris specimens were discriminated by the presence of Pb and Zn, while an evident preference for Cd and Cu was recorded in Squilla mantis. In addition, the distribution of heavy metals in organisms revealed sound differences between Follonica and Livorno sampling sites, demonstrating a highly heterogeneous anthropogenic impact in terms of heavy metals input from the industrial activity resting on land., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Silver nanoparticles (AgNPs) incorporation in commercial products is increasing due to their remarkable physical and chemical properties and their low cost on the market. Silver has been known for a long time to be highly toxic to bacterial communities, aquatic organisms, and particularly to marine biota. Strong chloro-complexes dominate Ag speciation in seawater and facilitate its persistence in dissolved form. It has a great impact on marine organisms because low concentration of silver can lead to strong bioaccumulation, partly because the neutral silver chloro complex (AgCl 0 ) is highly bioavailable. Owing to the fact that estuaries and coastal areas are considered as the ultimate fate for AgNPs, the study of their toxic effects on marine invertebrates can reveal some environmental risks related to nanosilver exposure. In an attempt to reach this goal, many invertebrate taxa including mollusks, crustaceans, echinoderms and polychaetes have been used as biological models. The main findings related to AgNP toxicity and marine invertebrates are summarized hereafter. Some cellular mechanisms involving nano-internalization (cellular uptake, distribution and elimination), DNA damaging, antioxidant cellular defenses and protein expression are discussed. Physiological effects on early stage development, silver metabolic speciation, immune response, tissue damaging, anti-oxidant effects and nano-depuration are also described. Finally, we paid attention to some recent interesting findings using sea urchin developmental stages and their cells as models for nanotoxicity investigation. Cellular and physiological processes characterizing sea urchin development revealed new and multiple toxicity mechanisms of both soluble and nano forms of silver.

The effect of different seasons on sterol content of seafoods was investigated. There were four sterols (cholesterol, sitosterol, desmosterol and stigmasterol) identified, with cholesterol being the predominant sterol. Stigmasterol was a minor component in fish muscle, whilst sitosterol was one of the main phytosterols found in fish muscle. Cholesterol content of fish consisted of 38-100% of total sterols in fish and 54-80% of total sterols in shellfish. The highest cholesterol content of fish muscle was found in summer and the lowest in autumn, whereas season did not have any effect on cholesterol level of green tiger prawn and speckled shrimp. Total sterol content of fish muscle ranged from 49 to 110 mg/100 g, although the range of total sterols in shrimp muscle was between 62 and 91 mg/100 g. The result of the study showed that total sterols in fish were generally found at lower levels in winter compared with other seasons.

Studies on the digestive secretions in aquatic animals can elucidate certain aspects of their nutritive physiology. The aim of the present study was to compare the digestive lipase and phospholipase activities in ten marine species belonging to four classes following the taxonomic classification of marine organisms. All aquatic digestive tissues tested are equipped with lipase and phospholipase activities, assuming the hydrolysis of fat-rich food. The lipolytic activities determined in the pancreases of cartilaginous fishes were greater than those in bony fishes, molluscs and crustaceans. This finding might be explained by the strong digestive utilization of fat-rich macronutrients by these carnivorous fishes. A trend of activities and stabilities at different pH and temperatures for crude lipases and phospholipases from these aquatic animals suggests that the optimum pH and temperature for marine lipases are species dependent. Interestingly, the sardine caecal lipase and phospholipase were found to be mostly stable in a broad range of acidic pH values. The maximum activities of lipolytic enzymes from the hepatopancreases of Hexaplex trunculus (molluscs) and Carcinus mediterranus (crustaceans) were found to be 50 and 60 °C, respectively, whereas the optimal temperature of lipolytic enzymes for the other species was classically around 40 °C. Thermoactivity of molluscs' lipolytic preparations makes them potential candidates in industrial applications. Among digestive glands studied, only pancreas (cartilaginous fish) contained the classically known colipase. Regarded as the most primitive living jawed vertebrates, cartilaginous fishes represented by sharks and rays could be considered as the oldest vertebrates possessing a complex digestive system like that of mammals.

Large amount of underutilized by-products are generated from the seafood processing plants annually. Consequently, researches have been initiated to investigate those discarded materials and have identified a number of bioactive compounds including bioactive peptides, collagen and gelatin, oligosaccharides, fatty acids, enzymes, calcium, water-soluble minerals, and biopolymers. Bioactive peptides derived from fish by-products have shown various biological activities including antihypertensive and antioxidant activities and hence may be a potential material for biomedical and food industries. Collagen and gelatin are currently used in diverse fields including food, cosmetic, and biomedical industries. Other than that, they are promising drug carriers for the treatment of cancer. Many studies have reported that chitin, chitosan, and their derivatives possess biologically active polysaccharides and hence they are potential agents for many applications. Further, those compounds have also showed potential activities such as antioxidant, antibacterial, antiviral, antihypertensive, anticancer, etc. Hence, seafood by-products are valuable natural resources that show range of functionalities and hence potential materials for biomedical and nutraceutical industries., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Levels of 18 polychlorinated biphenyl (PCB) congeners were determined by gas chromatography-mass spectrometry (GC-MS) in some marine species, living both in the coastal area and in deeper seawater. In some species analysis was performed separately in edible parts (fillets) and in viscera. The existence and degree of bioaccumulation was assessed studying individual species of very different size, with the smaller being younger. Furthermore, with a multivariate statistical analysis, a correlation between PCB congeners and the feeding habits and habitat of the fish was demonstrated. The results show that fat from edible parts (fish fillets) had total PCB levels in the range 22.6-601.9 µg kg⁻¹ (with 601.9 µg kg⁻¹ in anchovies), while fat from viscera showed much higher concentrations (407.3-916.6 µg kg⁻¹). Bioaccumulation was confirmed, comparing PCB levels between younger and older individual hake, squid, and horned octopus. The total PCB concentration ratio (older/younger individuals) ranges from 2.11 (squid = 292.1/137.8 µg kg⁻¹) to 3.46 (hake = 546.0/158.0 µg kg⁻¹).

The review reports on the presence and metabolism of sex steroids in several invertebrate species and provides detailed information on possible mechanisms of endocrine disruption other than the interaction with nuclear receptors. The presence of most vertebrate sex steroids in invertebrate tissues has been demonstrated by liquid or gas chromatography coupled to mass spectrometry. In addition, enzymatic pathways involved in the steroidogenic pathway have been described in at least some invertebrate phyla. Some endocrine disruptors induce alterations in these metabolic pathways and might lead to changes in steroid levels. Growing evidence suggests that estradiol can act through non-genomic pathways in molluscs, and that xenobiotics can as well interfere in these signalling cascades. In spite of these recent advances, most question marks on the action and function of sex steroids in invertebrates remain to be answered.

Fish collected from five different locations from the Calicut region, India were analysed for the levels of organochlorine pesticides (OCPs) and heavy metal (HM) residues in order to elucidate the status of these chemical contaminants in fish and shellfish meant for human consumption. The highest concentrations of OCPs detected in the edible portion of fish were 10.47, 70.57 and 28.35 ng g-1 wet weight, in marine, brackish water and freshwater, respectively. BHC and heptachlor epoxide formed the major share of OCPs in the marine fish while BHCs contributed to the major share in the freshwater and brackish water fish. The DDT (sum of DDT and its metabolites) ranged from 0.05 to 8 ng g-1 in the samples irrespective of the habitat. Among the HMs, Cu, Zn, Mn and Cr were present in the samples irrespective of the place of collection. About 22% of the samples from the freshwater area contained marginally higher lead content above the legal limit of 0.2-0.4 microg g-1. The Cr content ranged from 0.1 to 1.1 microg g-1 in the fish with marginally higher content in the fish from freshwater and marine regions (0.55-1.1 microg g-1). Mercury was detected in the samples (55%) from marine habitat only. The concentrations of OCPs and HMs in the samples, in general, were below the maximum residual level recommended by various organizations.

Marisa cornuarietis (Mollusc), Hyalella azteca (Crustacean), and Paracentrotus lividus (Echinoderm) demonstrated the ability to metabolize androgens through different pathways catalyzed by 5alpha-reductases (5alpha-R), hydroxysteroid dehydrogenases (HSD), hydroxylases, sulfotransferases (SULT), and fatty-acid acyl-CoA acyltransferases (ATAT). Interspecies differences and tissue-specific distribution of those enzymatic activities were observed. Xenobiotics, such as triphenyltin, tributyltin, and fenarimol, interfered with some of the pathways studied, namely, testosterone sulfation, testosterone esterification, and 5alpha-R activity. The work evidenced different sensitivity of those pathways to androgenic compounds, together with interphyla differences in androgen metabolism.

The aim of this work was to determine the immunolocalization of the antioxidant enzymes catalase, Cu,Zn-superoxide dismutase (SOD), Mn-SOD, and glutathione peroxidase (GPX) in the bivalve mollusks Mytilus galloprovincialis and Crassostrea sp., the crab Carcinus maenas, and the teleostean fish Mugil cephalus. By immunoblotting, crossreactivity between antibodies and the corresponding proteins in the digestive gland/hepatopancreas of invertebrates and the fish liver was demonstrated. Immunohistochemical studies showed that the stomach epithelium was strongly immunostained for catalase in mollusks. In crabs, ducts showed stronger immunostaining than tubules and in mullet hepatocytes the reaction appeared in discrete granules corresponding to peroxisomes. With regard to Cu,Zn-SOD, the apex of the tubule cells in mussels and crabs was distinctly immunostained, whereas in oysters the reaction was more marked in ducts and in mullet liver a uniform diffuse cytoplasmic staining was found. Mn-SOD was strongly positive in mollusk and crab ducts and in mullet periportal hepatocytes. Finally, GPX was not detected in mussels while in oysters a slight reaction was noted in all cell types. In crabs, connective tissue cells and the apex of duct cells were immunostained, but in mullet liver only erythrocytes appeared reactive. Immunoelectron microscopy revealed that catalase was localized in peroxisomes with a dense labeling in fish and less intense labeling in invertebrates. Cu,Zn-SOD was mainly a cytosolic protein although additional positive subcellular sites (peroxisomes, nuclei) were also observed, while Mn-SOD was restricted to mitochondria. GPX was localized in the cytosol, nucleus, and lysosomes, occurring also in peroxisomes of the fish liver. The results presented here provide a basis for future application of the immunodetection techniques to study the possible differential induction of antioxidant enzymes in aquatic organisms subjected to oxidative stress as a result of exposure to environmental pollutants.

Color plays a major role in the overall acceptability of food products. It is considered one of man's basic experiences that a particular foodstuff has to be of a distinct color in order to be edible. The color of a seafood is the first characteristic noted by the consumer and is directly related to the subsequent acceptance or rejection of it. Carotenoids contribute to the yellow, orange, and red colors of the skin, shell, or exoskeleton of aquatic animals. Indeed, they are the most widespread pigments found in nature, as they occur in bacteria, yeasts, mold, all green plants, and many animals, and therefore various functions have been attributed to them. From anthropocentric consideration, the most significant aspect of carotenoids is the color they impart to our food and environment. In animals, the carotenoids are also associated with reproductive organs and hence the hatching success and survival of alevins.

The goal of this work was to study the fate of dichloromethane in indoor aquatic microcosms after a sublethal and static exposure to simulate the accidental contamination of a lenitic ecosystem such as littoral lake zone or a pond. This kind of ecosystem is characterized by high productive capacity and rich biocoenose, and are usually first affected by acute or chronic pollution. Microcosms containing immersed bryophytes (Fontinalis antipyretica), macrophytes (Lemna minor, Groenlendia densa, Elodea canadensis), molluscs (Physa fontinalis), crustaceans (Daphnia magna), and unicellular green algae (Scenedesmus subspicatus) were contaminated with sublethal concentrations of dichloromethane or [14C]dichloromethane. The initial mean concentration was 9.9 +/- 3.7 microM. The mean concentration exposure for organisms was 4.5 +/- 1.5 microM. The fate of 14C radioactivity was monitored by measuring the radioactivity of the sediment, water, macro- and microorganism, and atmospheric compartments. Radioactivity in the water disappeared quickly from the microcosms, most likely as [14C]dichloromethane (t1/2 = 5.31 +/- 0.41 days). At the end of the experiments, radioactivity was mainly located in the atmosphere, with traces remaining in the biomass. Under static conditions, the bioaccumulation of 14C radioactivity from the radiolabeled dichloromethane was negligible.

Hydrocarbons and polychlorinated biphenyls (PCBs) were determined in tissues of marine organisms (mussels, crabs, benthic, and pelagic fishes) from six sites along the Catalan Coast (Western Mediterranean). Both aliphatic and aromatic hydrocarbons as well as seven PCB congeners (PCB-28, 52, 101, 118, 138, 153, 180) were quantified and differences in concentrations interpreted in terms of geographical distribution, trophic level, and biological cycle of the organisms. The bioaccumulation patterns of the different chemicals varied substantially. Hydrocarbons were metabolized along the food web, contrarily to PCBs, which exhibited a higher bioaccumulation in fishes. Considering 36 peaks of the GC-ECD profiles, encompassing 40 PCB congeners, from tri- to octa-chlorinated isomers, a relative enrichment was observed in the higher chlorinated ones from: mussels < mullets < tuna < crabs. The slopes of the correlation plots between the bioconcentration factor (log BCF) and the octanol-water partition coefficient (log K(ow)) for the different PCB congeners reflected the feeding behavior of the organisms, mussels exhibiting a preferential uptake by direct partitioning from water, and mullets and crabs with a certain uptake from sediments. Increasing metabolic degradation following a similar trend among species was also observed for aromatic hydrocarbons and PCB congeners containing meta and para vicinal H-atoms. Accordingly, mussels and benthic fishes were the best indicators of coastal pollution in the water column and sediments, respectively, although the above features should not be overlooked in the interpretation of biomonitoring data.

High levels of polynuclear aromatic hydrocarbon (PAH) carcinogens commonly occur in aquatic systems where neoplasms arise in fish and other animals. Enzymes that transform PAHs can act in initiating these diseases and can indicate the contamination of fish by carcinogens and other pollutants. Cytochrome P-450 has similar roles in activating PAH carcinogens in fish and mammalian species. PAHs and many chlorinated hydrocarbons, e.g., polychlorinated biphenyls (PCBs) induce a form of cytochrome P-450 in fish that is the primary catalyst of PAH metabolism. The induction of this P-450 in fish can accelerate the disposition of hydrocarbons, but can also enhance the formation of carcinogenic derivatives of PAHs. Invertebrates have lower rates of PAH metabolism than fish. These rates are not obviously inducible by exposure to PAHs or PCBs. The lower rates of foreign compound metabolism contribute to higher pollutant residue levels in bivalve mollusks (clams, mussels, etc.) than in fish and may limit the involvement of some procarcinogens (requiring activation) in disease processes in invertebrates. The induction of P-450 forms can indicate the exposure of fish to PAHs, PCBs, and other toxic compounds. This is not restricted to carcinogens. Environmental induction has been detected in fish from contaminated areas by use of catalytic assay, antibodies to fish P-450, and cDNA probes that hybridize with P-450 messenger RNA. Application of these methods can provide sensitive biological monitoring tools that can detect environmental contamination of fish by some carcinogens and tumor promoters.(ABSTRACT TRUNCATED AT 250 WORDS)

In marine fish and crustacean liver, degradative enzymes able to convert purines to urate have been shown to be located only in the cytosol, and degradative enzymes able to convert urate to urea and glyoxylate, only in the peroxisomes (Noguchi, T., Takada, Y., & Fujiwara, S. (1979) J. Biol. Chem. 254, 5272-5275). The subcellular distribution of these two enzymes involved in further metabolism of urea and glyoxylate in marine animal species was examined by centrifugation in a sucrose density gradient. Urease was located only in the cytosol of crustacean and mollusc liver; no activity was detected with fish liver. In fish, crustacean and mollusc liver, the conversion of glyoxylate to glycine may be mainly catalyzed by alanine : glyoxylate aminotransferase. Hepatic alanine: glyoxylate aminotransferase was located both in the mitochondrial matrix and in the cytosol in each species studied. These findings suggest that peroxisomal urea is transported to the cytosol then degraded to NH3 for the excretion of purine nitrogens, while peroxisomal glyoxylate is transported to the cytosol or mitochondria then converted to glycine for the reutilization of purine carbons.

1. The following carotenoids were isolated and identified: astaxanthin diester, tunaxanthin monoester, astaxanthin monoester, tunaxanthin, astaxanthin, doradexanthin, lutein, zeaxanthin, idoxanthin, triol and tetrol from nine species of fish; astaxanthin diester, astaxanthin monester, astaxanthin, doradexanthin, zeaxanthin, idoxanthin and tetrol from four species of crustacean, astaxanthin, pectenolone, pectenoxanthin, pectenol and tetrol from four species of scallop. 2. Tunaxanthin monoester and astaxanthin diester were major carotenoids in skipjack and Pacific cod, respectively. 3. The concentration of carotenoids ranged 0.065-1.95, 1.30-5.91 and 1.56-7.15 mg per 100 g ovary for fish, crustacean and scallop, respectively. 4. The species- and tissue-specificity of ovarian carotenoids and their possible role are discussed.

Two structurally related arthropod neuropeptides, red pigment concentrating hormone (RPCH) and adipokinetic hormone (AKH), are potent excitors of the heart of the clam Mercenaria mercenaria. The response is bimodal: whereas the threshold for affected hearts is 1-3 X 10(-9) M, about 40% of the preparations are virtually unresponsive. Aqueous extracts of Mercenaria ganglia contain a substance which concentrates the red pigment in the erythrophores of intact destalked Uca pugilator and even of its isolated legs. This substance is retained on Sephadex G-15 and co-elutes with synthetic shrimp RPCH. The active fractions also concentrate the erythrophores and the leucophores of destalked shrimp (Penaeus). Neither dopamine nor the molluscan neuropeptide FMRFamide had any chromatophorotropic effect in these assays. The activity of the ganglion extracts was abolished by digestion with chymotrypsin. In conclusion, molluscan ganglion extracts contain a peptide factor, possibly an analog of RPCH, that concentrates the pigments of crustacean chromatophores by a direct action on the cells.

By comparing environmental anaerobiosis with exercise anaerobiosis it appears that animals with high anoxia tolerance use (partly) different types of metabolic reactions to sustain energy metabolism, whereas low tolerance animals (Arthropoda, Echinodermata, Vertebrata) use the same pathway under both conditions. During exercise anaerobiosis the classical glycolysis (lactate pathway) is a main pathway among all multicellular organisms, although in marine invertebrates--except the Arthropoda and Echinodermata--it mostly does not terminate in lactate. During environmental anaerobiosis Cnidaria, Mollusca, Annelida and Sipunculida first couple additional pathways for energy extraction to the glycolytic pathway (the aspartate--succinate pathway) and later deviate the main carbon flow of glycogen at the level of phosphoenolpyruvate towards succinate, propionate and acetate production. Metabolic adaptations to anoxic cellular conditions in these groups are high fuel stores, increased ATP yield by anaerobic sources, formation of easily excretable (volatile) end products, an aspartate-dependent system for transport of hydrogen through the inner membrane of the mitochondrion and a rapid recovery from anaerobic metabolism. During anaerobic conditions three sources can contribute to the anaerobic power output, endogenous stores of both ATP and phosphagen and catabolism. Anaerobic power output rates have been calculated for a number of Mollusca, Annelida and Crustacea. Extreme anoxia resistance is coupled to a strongly reduced metabolic rate. In animals with high aspartate stores, the aspartate--succinate pathway and phosphagen hydrolysis can provide sufficient ATP during environmental anaerobiosis; however, with exercise anaerobiosis when ATP turnover rates may be increased by a factor of 20, pyruvate derivatives simultaneously accumulate in high amounts relative to succinate.

The phenolic metabolites of biphenyl in the crustacean Cirolana borealis LILJEBORG (ISOPODA), the gastropod Buccinum undatum L and the ophiuroid Ophiocomina nigra ABILDGAARD have been analysed qualitatively and semi-quantitatively as trimethylsilyl (TMS) ethers by combined gas chromatography/mass spectrometry and gas chromatography, respectively. The findings demonstrate the in vivo metabolic capacity of these organisms to convert biphenyl into its hydroxylated derivatives. Thus, 2-hydroxybiphenyl is the most prominent metabolite detected in all these experiments, which also showed that minor amounts of the 4-hydroxy and 4,4'-dihydroxy metabolites are formed. Metabolites of biphenyl origin are found both in the sea water from the aquaria and in the tissue of the respective marine organisms. The experiments, moreover, indicate a slow metabolism of biphenyl in C. borealis, B. undatum and O. nigra, between which no qualitative metabolic differences are found.

Concentrations of chlorinated pesticides and polychlorinated biphenyls (PCB's) were determined in three offshore marine species from the Oregon/Washington coast: pink shrimp, euphausiids, and flatfish; five species of bivalve mollusks from five estuaries along the Oregon coast; several fish species from the Coos Bay and Columbia River estuaries; and a summer run of steelhead from the Rogue River. The compounds p,p'-DDE and PCB's were detected most frequently. Euphausiids and pink shrimp contained approximately 2 ppb (mug/kg) wet-weight DDE and 8 and 25 ppb PCB's, respectively. Offshore flatfish contained an average of 9 ppb DDE and 29 ppb PCB's. DDE residues in estuarine mollusks approximated 0.5 ppb. PCB levels were not detectable (greater than 3 ppb) except in collections from the mouth of the Columbia River where the levels averaged 400 ppb PCB's and 17 ppb DDT. Selected Columbia River where levels averaged 400 ppb PCB's and 17 ppb DDT. Selected Columbia River fish species contained 38 ppb DDE and 480 ppb PCB's; summer-run steel-head in the Rogue River contained 97 ppb DDE and 125 ppb PCB's. PCB chromatograms of most euphausiids closely resembled those of Aroclor 1254. Chromatograms of shrimp and flatfish indicated selective metabolism of two compounds in the Aroclor 1254 formulation. Biphenyls of higher chlorine content were also detected in the shrimp and flatfish.

Metallothionein-like proteins have been isolated from marine invertebrates. Three crustaceans, Scyllus serratus, Cancer magister and Acetes sibogae together with a mollusc, Cryptochiton stelleri, have been investigated. S. serratus hepatopancreas was shown to contain cadmium and zinc inducible metallothionein-like proteins with an amino acid analysis very similar to vertebrate metallothioneins. The molecular weight, ultra-violet spectrum and isoelectric points of S. serratus metallothioneins are also comparable to the vertebrate proteins, suggesting a fundamental biological function conserved throughout evolution.