Concentration and distribution of heavy metals in tissues of two cephalopods,Eledone cirrhosa and Sepia officinalis,from the French coast of the English Channel

The concentrations of 11 heavy metals (Ag, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn) were measured in the tissues (digestive gland, branchial hearts, gills, digestive tract, kidney, genital tract, muscle, skin, shell) of the two cephalopods Eledone cirrhosa (d'Orb.) and Sepia officinalis (L.) collected from the French coast of the English Channel in October 1987. The tissues of both species displayed a similar pattern of heavy-metal accumulation: the digestive gland, branchial hearts and kidney were the major sites of concentration for all 11 metals; the digestive gland accumulated silver, cadmium, cobalt, copper, iron, lead and zinc, the branchial hearts high concentrations of copper, nickel and vanadium, and the kidney high concentrations of manganese, nickel and lead. The digestive gland, which constituted 6 to 10% of the whole-animal tissue, contained >80% of the total body burden of Ag, Cd and Co and from 40 to 80% of the total body burden of the other metals. The ratios between heavy metal concentrations in the digestive gland and those in the muscle separated the elements into three groups, those with a ratio 10 (Cr, Mn, Ni, Pb, V, Zn), those with a ratio >10 to <50 (Co, Cu, Fe), and those with a ratio 50 (Ag, Cd). The digestive gland of cephalopods (carnivorous molluscs whose age can be easily calculated with great accuracy) would seem to constitute a good potential indicator of heavy metal concentrations in the marine environment.     

Tissue distribution of the amnesic shellfish toxin,domoic acid,in<Emphasis Type="Italic"> Octopus vulgaris</Emphasis> from the Portuguese coast

Domoic acid (DA), the amnesic shellfish toxin, is a food-web-transferred algal toxin that has been detected in many marine organisms from copepods to whales. However, cephalopods, which are important members of the food chain, have never been implicated in DA transfer or accumulation. Here, we present data showing relevant values of DA detected in the common octopus (Octopus vulgaris) from the Portuguese continental coast. Even though DA is hydrophilic and is not expected to be accumulated in the tissues, DA was always detected in our octopus tissue samples. Tissue distribution of DA revealed that the digestive gland and the branchial hearts are the main organs of DA accumulation. Highly variable DA concentrations, ranging from 1.1 to 166.2 g DA g^–1, were observed in the digestive glands. Low levels of DA were detected in the digestive tract (stomach and intestine) and could be a consequence of high digestion rates or a result of non-exposure to toxic vectors during the sampling period. In fact, octopus prey, such as bivalves, crustaceans and fishes, are known to occasionally work as DA vectors. Consequently, DA uptake into octopus tissues is likely sporadic. Similar low levels were detected in the kidney, gills, systemic heart, posterior salivary glands and mantle, and no DA was found in either the gonads or the ink sac. These data are the necessary first step towards achieving an understanding of the accumulation of phycotoxins in O. vulgaris.Communicated by S.A. Poulet, Roscoff     

Tissue and sub-cellular distribution of Fe,Cu, Zn and 210Po in the abalone Haliotis rubra

The tissue and sub-cellular distribution of Fe, Cu, Zn and the naturally occurring radionuclide polonium-210 was determined in the gastropod mollusc Haliotis rubra collected from Western Port Bay, Australia, between March and July 1988. The highest concentrations of the metals, with the exception of Cu, were found in the digestive gland. Copper was more uniformly distributed, with tissues that are more vasculated having higher concentrations. Ultrastructural examination of the digestive gland, gill and kidney showed dense membrane-bound granules within the cytoplasm. Elemental analysis of the granules by electron probe x-ray microanalysis indicated that the granules in the digestive gland and gill contained high concentrations of iron, with small amounts of copper and zinc. In contrast, the metal-containing granules in the kidney were predominantly composed of iron, copper and phosphorus, with variable contributions of sodium potassium, and calcium. Homogenisation and fractionation of the digestive gland by differential centrifugation confirmed that approximately 80, 10, 90 and 50% of the total homogenate Fe, Cu, Zn and ²¹⁰Po, respectively, sedimented at 1200xg. In the haemolymph, all the elements studied were associated with the soluble high molecular weight component of the serum, not with the amoebocytes. ²¹⁰Po was present in the mucus-secreting hypobranchial glands at about half the concentration found in gill tissue.     

Three new modes of luminescence in the leiognathid fish Gazza minuta: Discrete projected luminescence,ventral body flash,and buccal luminescence

Three new modes of luminescence are described for Gazza minuta (Bloch) (Perciformes: Leiognathidae) as observed in specimens collected in the Philippines in April and May, 1982: discrete projected luminescence (DPL), ventral body flash, and buccal luminescence. DPL sharply contrasts with previously reported modes of diffuse luminescence in leiognathids (counterillumination and opercular flash) in being a pair of bright collimated beams of light emanating from the fish in an anteroventral direction. The brightness, coherence, directionality, and control of DPL suggest striking similarities to luminescence in anomalopid (flashlight) and monocentrid (pinecone) fishes and perhaps in certain apogonids (cardinalfishes). The structural correlate for DPL is a small clear patch of skin lying at the posterior margin of each opercular cavity. Luminescence from the internally located light organ traverses transparent bone and translucent muscle before passing through the clear skin of the patch area. Behavioral and anatomical observations of ventral body flash and buccal luminescence are also presented. These new modes of luminescence indicate a much greater than expected diversity of luminescent behaviors in leiognathids, perhaps greater than that of any other organism yet studied. The internal location of the light organ is recognised as providing the potential for this diversity.     

Presence of coelenterazine in mesopelagic fishes from the Strait of Messina

Coelenterazine, a luciferine, and luciferase activity specific to coelenterazine were detected and assayed in various tissues of mid-water fishes, Argyropelecus hemigymnus, Chauliodus sloani, Myctophum punctatum, Vinciguerria attenuata and Cyclothone braueri. Coelenterazine was found mainly in digestive systems and photophores of these fishes. A large species to species variation was found: extremely high levels of coelenterazine and luciferase were found in the M. punctatum digestive system whereas only a very low level of coelenterazine was detected in C. braueri. Coelenterazine was detected in A. hemigymnus eggs supporting the hypothesis of a maternal transfer of luminous capabilities. Luciferase activity specific to coelenterazine was found in photophores as well as in various other tissues suggesting another (besides light emission) biological function for this enzymatic activity. Distribution of coelenterazine in all tissues of the individuals supports the hypothesis of the dietary acquisition of coelenterazine by these fishes.     

稻米来源镉对生长期猪的生长特性及不同脏器组织镉蓄积的影响

环境中的镉污染对动植物及人类都带来了极大的危害。目前,多数镉毒理研究关注其无机状态,而来源于稻米的有机态镉的毒害作用报道较少。为评估稻米来源镉对生长期猪的毒性作用,选用初始体重为30 kg左右的健康生长猪28头,随机分为体重无明显差异的2组,即对照组与稻米来源镉组(试验组),研究稻米来源镉对生长期猪(生长及育肥全阶段)的生长特性及不同脏器组织镉蓄积的影响。结果表明,在生长及育肥阶段,试验组与对照组相比:1)生长特性无显著差异(P0.05);2)育肥期组织游离氨基酸含量,除肌肉中的赖氨酸显著降低外(P0.05),血浆、肝脏、肾脏及肌肉中其他游离氨基酸水平均无显著差异(P0.05);3)心脏、肝脏、脾脏、肾脏、肺脏、胃、小肠、大肠、骨骼中镉蓄积量显著增高(P0.05),而肌肉、血液中无显著差异(P0.05),脂肪、皮中未检出镉。日粮使用大比例镉超标稻米后镉在各脏器和组织中的蓄积规律为肾脏肝脏小肠脾肺大肠胃血液骨头心腿肌背肌脂肪、皮。由此可见,镉超标稻米对生长期猪的生长特性未产生显著的影响,稻米来源镉主要蓄积于肝脏和肾脏,而主流食用组织肌肉和血液中镉的蓄积量较少。     

Lysozyme and chitinase in blood and lymphomyeloid tissues of marine fish

The enzyme lysozyme (muramidase) has a degrading effect on chitin, but chitinase is more effective in this respect. Both enzymes occur in fish, but their distribution and function are poorly known. Activities of lysozyme and chitinase were measured in body fluids and tissues of marine fish. Lysozyme was estimated by a plate method, chitinase by a viscosimetric method with glycol chitin as substrate. pH optima and other characteristics were studied. Lysozyme was found in lymphomyeloid (haematopoietic) tissues of chondrichtyan fish (rays, shark, Chimaera monstrosa) and in the plasma and lymph of certain teleosts. Chitinase occurred in lymphomyeloid tissues (except thymus) of chondrichthyans and teleosts, and in the plasma and lymph of teleosts. The results indicate that these enzymes are normal components of fish blood. Probably they are produced by the granulocytes, white blood corpuscles rich in lysosomes. The enzymes might have defence functions in fish blood. Lysozyme is bacteriolytically active while chitinase possibly offers protection against chitincontaining parasites. Very high chitinase activity was found in the pancreas of C. monstrosa. The pancreatic enzyme probably has a digestive function.     

Digestive enzymes in marine invertebrates from hydrothermal vents and other reducing environments

The present study demonstrates the potential hydrolytic activities in the symbiont-containing tissues of the vent invertebrates Riftia pachyptila, Bathymodiolus thermophilus (collected in 1991 at the East Pacific Rise) and the shallow-water bivalve Lucinoma aequizonata (collected in 1991 from the Santa Barbara Basin). Activities of phosphatases, esterases, -glucuronidase and leucineaminopeptidase were comparable to those of digestive tract tissues of other marine invertebrates. A lack in most glycosidases as well as in trypsin and chymotrypsin was observed. Activities of lysozyme and chitobiase were rather high. In all vent invertebrates with symbionts and in L. aequizonata, the symbiont-containing tissues and the symbiont-free tissues had similar levels of enzymatic activities, indicating that polymeric nutrients could be hydrolysed after release from the symbionts and cellular uptake. The high activities of -fucosidase in all vent invertebrates as well as in the shallow-water bivalve L. aequizonata could point to the existence of a yet undescribed substrate available to hydrolysation. The ectosymbionts-carrying polychaete Alvinella pompejana (collected in 1991 at the East Pacific Rise, EPR) shows high lysozyme activities in its gut, consistent with the proposed food source of bacteria. For the vent crab Bythogrea thermydron (also collected in 1991 at the EPR) hydrolytic activities were highest in the gut, dominated by esterase and peptidase activities which support their proposed carnivorous food source. A snail and a limpet collected from R. pachyptila tubes showed high levels of chitobiase suggesting a food source of grazed bacteria or ingested R. pachyptila tube.     

有机磷农药对缢蛏[Sinonovacula constricta (Lamarck)]显微结构的影响

在实验室模拟缢蛏的生长环境,研究乐果和三唑磷对缢蛏的毒性效应.以气相色谱法测定缢蛏体内有机磷农药的含量,并通过光镜观察有机磷农药对缢蛏鳃和消化腺显微结构的影响.结果表明:缢蛏体内乐果和三唑磷的含量随着水体中有机磷农药的增加而增加,有很好的剂量-效应关系,但是无线性相关性.乐果和三唑磷对缢蛏鳃显微结构的影响是:鳃丝变短,鳃丝间隔和基底膜结缔组织增生,鳃孔、血管腔堵塞;不同的是:在乐果胁迫下,上皮细胞纤毛脱落严重,而三唑磷胁迫下,上皮细胞纤毛增生.乐果和三唑磷对缢蛏消化腺显微结构的影响主要表现为腺细胞界限模糊,腺泡水肿变形、部分坏死;结缔组织增生,细胞间质疏松,出现许多空泡;有机磷农药的浓度高时消化腺细胞变性、坏死,细胞质囊泡化.     

Pathological effects of sublethal diazinon on the blood,gill, liver and kidney of the freshwater fish Capoeta damascina

Capoeta damascina has a large distribution in the Middle East and is one of the most abundant fishes in inland waters of Iran. Histopathological symptoms of the blood, gill, liver and kidney of C. damascina were investigated over 1, 5 and 9-day exposure to 0 (control), 0.5, 1 and 1.5?mg?L^?1 diazinon. The data were analysed using analysis of variance and non-parametric multivariate analysis of variance. Diazinon concentration was more important than the exposure time on changes of the tissues. Diazinon decreased red blood cell (RBC), white blood cell (WBC), haematocrit (Hct) and haemoglobin (Hb). The symptoms of the gill were mainly desquamation, epithelial hyperplasia, hyperplasia at the base of secondary lamella, epithelial lifting and curling. The prevalent symptoms of the liver were degeneration of nuclei, alternation in size and shape of hepatocytes, focal necrosis and pyknosis. Degeneration of Bowman's capsule, necrosis in renal tubule and haematopoietic tissue were the most common symptoms found in the kidney. In conclusion, the blood, gill, liver and kidney of C. damascina are sensitive enough to respond to low concentrations of diazinon over a short period and this species can thus be a bioindicator of diazinon.     

Assessment of non-invasive techniques for monitoring mercury concentrations in species of Amazon turtles

This study determined the concentrations of mercury (Hg) in four tissues of six species of turtles from the Rio Negro in the Amazon Basin. For two species, blood and carapace tissues were correlated with concentrations in internal tissues to establish whether blood or carapace could serve as a non-lethal indicator of internal metal exposure or body burden. The four tissues’ Hg levels were also correlated to turtle size and gender. The liver in five species of turtles had the highest concentration, followed by carapace, muscle, and blood. The exception was Chelus fimbriatus, which had a higher metal concentration in the muscle than carapace. Regarding the correlation between total Hg concentrations in tissues of the two species, no significant correlation was noted for Podocnemis erythrocephala. However, for Podocnemis sextuberculata significant correlation was found between muscle?×?liver, muscle?×?blood, and liver?×?blood. For P. erythrocephala, there was a correlation between Hg concentration in carapace and turtle size. For P. sextuberculata, there was no marked correlation between Hg concentration and size, but concentration in muscle was significantly influenced by gender. The patterns of Hg accumulation in tissues of the five species followed those described for freshwater species and some species of sea turtles. The difference in C. fimbriatus may be a result of a different pattern of non-living keratin layers on the carapace tissue. The use of carapace to infer internal concentrations of Hg is common in freshwater and sea turtles, but in this study it was found that only blood might be a reliable indicator of Hg concentrations in liver and muscle tissues for P. sextuberculata. Thus blood may be used as a non-invasive method to study concentrations of Hg in liver and muscle of P. sextuberculata.     

Tissue,ontogenic and sex-related differences in δ<Superscript>13</Superscript>C and δ<Superscript>15</Superscript>N values of the oceanic squid <Emphasis Type="Italic">Todarodes filippovae</Emphasis> (Cephalopoda: Ommastrephidae)

Stable isotopes are increasingly used in the study of trophic interactions of many aquatic animals and most recently cephalopods. To evaluate the application of the method to squids, it is important to assess isotopic differences among and within consumer tissues that may confound the resolution of ecological relationships. Inter- and intra-tissue isotopic variation was examined in 55 individuals of the oceanic squid Todarodes filippovae that were collected at the beginning of April 2000 in the southwestern Indian Ocean (between 44°S, 76°E, and Saint Paul and Amsterdam islands, 38°S, 78°E). Delipidated soft tissues (mantle, arm, buccal mass, gill and reproductive organs) showed small δ¹³C and δ¹⁵N differences, which were probably tissue-specific. A lower carbon value was observed in the digestive gland as a consequence of incomplete lipid removal. Hard tissues, such as beaks and gladii, had lower ¹⁵N values than soft tissues, which can be explained by the presence of chitin, a ¹⁵N-depleted molecule. Females (n = 38) and males (n = 17) had identical δ¹³C values, but females showed higher δ¹⁵N values than males. The difference was size-related rather than sex-related, however, as females were generally larger than males. A comparison of similar-sized females and males produced identical nitrogen values. These data suggest dietary shifts from lower to higher trophic levels during growth, because δ¹⁵N values of large T. filippovae were much higher than that of small specimens. As expected, nitrogen values of lower beaks and gladii of large squids increased from the oldest to the most recently formed region, reflecting the progressive growth of chitinized tissues in parallel with dietary changes. Sequential sampling along the growth increments of squid beaks and gladii can likely be used to produce a chronological record of dietary information throughout an individual’s history.     

Petroleum hydrocarbons in the marine bivalve Venus verrucosa: accumulation and cellular responses

Cellular and subcellular responses of the marine burrowing bivalve Venus verrucosa collected from the north-eastern coastline of Malta from January to June 1985, after exposure to petroleum hydrocarbons (PHC) were investigated. After long-term exposure to 100 gl^-1 of water-accomodated fractions (WAF) of crude oil, PHC were found to accumulate most rapidly in the digestive gland and then in the gills, with saturation levels being reached within 100 d of exposure in both cases. PHC accumulation, both in the mantle and muscle tissues, was more gradual and consistent throughout the whole exposure period. After 150 d of exposure, the digestive cells of the digestive gland were significantly reduced in height (atrophy) and exhibited reduced lysosomal membrane stability. After 144 h of exposure to higher concentration of PHC (820 and 420 gl^-1), several cytological effects were recorded, including an increase in cell volume and activity of gill mucocytes as well as in the number of haemocytes in gill blood sinuses. There was also evidence of damage to the epithelial lining of the foot, stomach and style sac and marked atrophy of the digestive cells of the digestive gland. The significance of such responses is discussed.     

Interspecific variation of heavy metal concentrations in the different tissues of tropical intertidal gastropods from Malaysia

The present study aims to determine the concentrations of Cd, Cu, Fe, Ni, Pb, and Zn in the different tissues of five species of tropical intertidal gastropods from Malaysia. Each of the species have organs/tissues that highly accumulated certain metals. For Cu, the mantles of Cerithidea obtusa, Pugilina cochlidium, and Murex trapa; and the digestive caeca of Thais sp. and Chicoreus capucinus highly accumulated Cu. The shells of Chi. capucinus and M. trapa, the digestive caeca of P. cochlidium, and the digestive glands of Thais sp. and Chi. capucinus highly accumulated Cd. The tentacles and the digestive caeca of Cer. obtusa and P. cochlidium, respectively, highly accumulated Zn, the digestive glands of Thais sp., Chi. capucinus, and M. trapa also highly accumulated Zn. The shells of most of the gastropods accumulated high levels of Pb and Ni. The opercula of most of the gastropods, besides the digestive glands for Thais sp., accumulated high levels of Fe. The present study on interspecific variations of heavy metals in gastropods provided information on differences of metal distributions in the different tissues, which could be useful in proposing potential tissues as better biomonitoring tools of heavy metal bioavailabilities in the coastal waters of Peninsular Malaysia.     

Biochemical composition of cephalopods with different life strategies,with special reference to a giant squid,<Emphasis Type="Italic"> Architeuthis</Emphasis> sp.

The present study is a comprehensive comparison of the biochemical composition (protein, lipid, glycogen and cholesterol contents, and amino acid and fatty acid profiles) of 14 species of cephalopods with different life strategies (benthic, nektobenthic, benthopelagic and pelagic) in distinct habitats (neritic, demersal, oceanic and deep sea), with special emphasis placed on a male Architeuthis sp. The giant squid showed a significantly lower protein and total amino acid content in the gonad and digestive gland. The major essential amino acids were leucine, lysine and arginine. The major non-essential amino acids were glutamic acid, aspartic acid and proline. The benthopelagic cirrate octopus Opisthoteuthis sp. showed a lower content of these nitrogen compounds in the muscle. In respect to lipid and fatty acid contents, the giant squid showed the highest values in the gonad and digestive gland and the lowest in the muscle. Most of saturated fatty acid content was presented as 16:0; monounsaturated fatty acid content, as 18:1 and 20:1; and polyunsaturated fatty acid content, as 20:4n-6, 20:5n-3 and 22:6n-3. The highest cholesterol content in the gonad was detected in Opisthoteuthis sp. and Architeuthis sp.; in the digestive gland. in Todarodes sagittatus; and in the muscle, in Sepia elegans. The highest glycogen value in the gonad was detected in Octopus vulgaris; in the digestive gland and muscle, the highest values were attained in Opisthoteuthis sp. The relationships between life strategies and biochemical composition were investigated and principal component analysis (PCA) was performed. The different cephalopod life strategies could be well separated on the basis of the first two principal components. The nektobenthic and pelagic strategies were clearly separated from the benthic, suggesting that these groups of species are characterized by lower lipid content and higher protein content in the gonad. A rather similar life-strategy distinction was obtained for the digestive gland. The benthopelagic strategy was also well separated from benthic and pelagic strategies and from Architeuthis sp. In the muscle, the results indicated lower nitrogen and carbon compound contents in Architeuthis sp. and Opisthoteuthis sp. The environmental conditions that possibly explain the Architeuthis sp. stranding, the relationships between biochemical compositions and the life strategies of the different cephalopod species studied are discussed.Communicated by S.A. Poulet, Roscoff     

Trophic ecology of Grey-headed albatrosses from Marion Island, Southern Ocean: insights from stomach contents and diet tracers

During chick-rearing, albatrosses can alternate between long foraging trips that provide the main source of food for the adults and short foraging trips that they use to feed their young. This flexibility in foraging behaviour can lead to differences in diet composition between adults and chicks and implies that they may be vulnerable in different ways to food shortages. The trophic ecology of the Grey-headed albatross Thalassarche chrysostoma was investigated at the sub-Antarctic Prince Edward Islands during the chick-rearing period in April 2006 using a combination of approaches. Diets of adults and chicks were assessed using stable isotope ratios and fatty acid (FA) profiles of blood and/or stomach oils, in addition to stomach contents analysis. Fish from the family Macrouridae and cephalopods (particularly the onychoteuthid Kondakovia longimana) were the primary prey, whereas crustaceans (krill Euphausia superba) represented a smaller proportion of the stomach contents. Stomach oil FA profiles contained more monounsaturated FA than the profiles of plasma, which were richer in saturated FA and arachidonic acid (20:4n-6). There was also a distinct separation of adults from chicks, with higher levels of monounsaturates in chick plasma, and higher saturated FA levels (particularly 16:0) in the adult plasma. Stable carbon isotope ratios of whole blood were similar in adults and chicks, whereas stable nitrogen isotope ratios showed significant enrichment by >1‰ in chicks. The combined FA, stable isotopes and stomach contents analyses suggest clear differences in diet quality between adults and chicks, with chicks feeding at a higher trophic position through feeding more on highly nutritious fish and adults keeping much of the less nutritious zooplankton for themselves.     

Two populations of the marine fish Porichthys notatus,one lacking in luciferin essential for bioluminescence

Porichthys notatus is a common benthic fish found along the Pacific coast of North America. It possesses more than 700 small dermal photophores on its head and trunk. When P. notatus collected in Monterey Bay, California, is injected subcutaneously with norepinephrine, the photophores emit a long-lasting luminescence that is readily visible to the dark-adapted eye. The light emission is due to the oxidation of luciferin (substrate) by molecular oxygen, catalyzed by luciferase. In contrast, P. notatus collected in Puget Sound, Washington, is nonluminous, even though the photophores do not differ ultrastructurally from those of the California fish. The inability of the Puget Sound fish to luminesce is due to lack of luciferin in its photophores. Luminescence capability, however, may be induced in the Puget Sound fish by the oral or intraperitoneal administration of a small amount of luciferin from the tiny luminescent marine ostracod crustacean, Vargula hilgendorfii, suggesting that the origin of luciferin in P. notatus may be from the diet. In this study, specimens of P. notatus were collected over the entire known range of the species, between November 1981 and September 1987, and the presence of luciferin in the photophores determined. The results indicate that there are two populations of P. notatus: a luciferin-deficient, nonluminescent population located north of northern California and a luciferin-containing, luminescent population extending south of Cape Mendocino, California, to Baja California, Mexico. At the northern end of the southern population, a mixture of luminescent and nonluminescent P. notatus was found.     

Distribution of enzymes of glycolysis and gluconeogenesis in fish tissues

Gluconeogenesis in fishes has been demonstrated in whole animals and liver preparations. However, at present, the relative physiological importance of possible substrates such as lactate, pyruvate and amino-acids or the precise sites of gluconeogenesis are unclear. In mammals, gluconeogenesis takes place in the liver and kidney, and the same could occur in fishes although it has been proposed that fish red muscle is also capable of reconverting lactate (derived from white muscle) to glucose. In this present study, the activities of 3 key glycolytic (hexokinase, phosphofructokinase and pyruvate kinase) and 2 key gluconeogenic (fructose diphosphatase and phosphoenolpyruvate carboxykinase) enzymes were investigated in tissues of the rainbow trout Salmo gairdneri, the cod Gadus morhua, and the plaice Pleuronectes platessa in order to elucidate the relative glycolytic/gluconeogenic capacities of the individual fish tissues. The glycolytic enzymes were found in all tissues, the relative potential being skeletal muscle>heart, brain >kidney, gills>liver. The gluconeogenic enzymes were not present in all tissues, and were mainly concentrated in the liver and kidney. Hence the results indicate that the liver, and to a lesser degree, the kidney are the major sites of gluconeogenesis in fishes, and that the process is unlikely to occur in skeletal muscle.     

Lindane toxicity range-finding test in Senegal sole (Solea senegalensis) juvenile: note on histopathological alterations

The purpose of this study was to examine the sublethal and/or lethal effects produced by exposure of teleostean fish Solea senegalensis to γ isomer of lindane, γ-hexachlorocyclohexane (γ-HCH). S. senegalensis was exposed to 0.1, 1 or 10 mg L^?1 of lindane for 96 h. Samples of different tissues (gills, liver and kidney) were extracted and processed for histopathological observations. The 72 h LC₅₀ value of pesticide was found to be 0.16 ± 0.04 mg L^?1 γ-HCH. Histological observations including aneurysms and hypertrophy of lamellar epithelia in gills, blood stagnation and vacuolization in liver and alterations in the hematopoietic tissue in kidney were observed. The results of the study show the sensitivity of juvenile of S. senegalensis to lindane and histology as a reliable tool to detect the sublethal effects of pollutants on the environment and aquatic biota. The toxicological implications arising from these results are the subject for further multi-concentration tests useful in establishing water quality criteria.     

Coelenterazine distribution and luciferase characteristics in oceanic decapod crustaceans

Coelenterazine biosynthesis has recently been demonstrated in the developing eggs of the decapod Systellaspis debilis. The cellular source of coelenterazine and the potential for biosynthesis in adult decapods, however, have not been fully investigated. We have conducted a systematic study of coelenterazine content in >230 individual decapods representing 19 species of Oplophoridae and 22 species from other families. We show for the first time that coelenterazine is responsible for both secretory and photophore luminescence in the same decapod. Tissues associated with secretory luminescence (hepatopancreas and stomach) in the Oplophoridae contained almost 3 orders of magnitude more coelenterazine (mean value=2154 pmol per specimen) than cuticular photophores (mean value=8 pmol per specimen). Coelenterazine content increases by 2 to 4 orders of magnitude during the development of three species of Oplophoridae. Species of Oplophoridae contain an order of magnitude more coelenterazine than those of other families (mean value=154 pmol per specimen). Coelenterazine was also detected in 11 apparently nonluminous decapod species (mean value=200 pmol per specimen). S. debilis luciferase characterisation enabled a luciferase assay to be developed to facilitate studies of the environmental control of bioluminescence. We hypothesise that the coelenterazine requirement in secretory bioluminescence exceeds that which could be assimilated from the food-chain. The significant increase of coelenterazine during the life cycle of secretory decapods supports this hypothesis. Putative evidence for environmental control of coelenterazine luminescence is also reported.