Distribution of calcitonin gene-related peptide and calcitonin-like immunoreactivity in trout.

Radioimmunoassay and chromatography were used to study the occurrence of calcitonin gene-related peptide in various tissues of the rainbow trout, Salmo gairdnerii. The highest concentrations of the peptide were found in gill (1.68 +/- 0.09 ng/mg protein) and in intestine (1.06 +/- 0.4 ng/mg protein). Significant concentrations were also found in heart and stomach. The level in brain was very low. In trout, the plasma concentration accounted for 283 +/- 82 pg/ml. Chromatographic analysis of the calcitonin gene-related peptide (CGRP)-like immunoreactivity occurring in gills showed that two molecular forms cross-reacted with the anti-human CGRP antibody, one co-eluting with the synthetic human CGRP. In addition, calcitonin in fish is not confined to the ultimobranchial organ but is also present in organs as heart, intestine, kidney, spleen and stomach. The evidence of CGRP in fish emphasizes the role of this hormone in evolution and leads us to investigate its physiological role in this species.

Selenium-induced autometallographic demonstration of endogenous zinc in organs of the rainbow trout, Salmo gairdneri.

Autometallographic (AMG) silver enhancement of endogenous zinc was studied in seven organs of the rainbow trout Salmo gairdneri. Groups of trout were injected intraperitoneally with sodium selenite in doses ranging from 0.08 to 25 ppm, administered 1 h before being killed. The concentration of selenium obtained by each organ was determined by gamma-spectrometry, and compared with the autometallographic deposition of silver grains. The relative accumulation of selenium in the organs was: liver greater than spleen greater than kidney greater than intestine greater than gills greater than brain greater than muscle. In the fish labelled with 10 and 25 ppm Se, AMG-deposits were found (1) within lysosomes of liver cells, (2) within the granules and on the nuclear membrane of melanophores in the spleen, (3) on the microvilli and in the apical cytoplasm of renal proximal tubular cells, (4) within the granules and along the plasma membrane of intestinal eosinophilic granule cells, and in the apical portion of the intestinal epithelium, and (5) in the gills, within granule cells and on the surface of the ionocytes. In the trouts injected with 5 ppm Se, silver grains were still observed in the liver, the intestine, and the gills, whereas, no such grains were found in preparations from fish having received 1 ppm Se. The use of selenium for the histochemical demonstration of endogenous zinc versus exogenous metals is discussed. Also, consideration is given to the question of which part of the total tissue zinc that is histochemically reactive.

Ultrastructural features of chloride cells in the gill epithelium of the Atlantic salmon, Salmo salar, and their modifications during smoltification.

To elucidate the ultrastructural modifications of the gill epithelium during smoltification, gills of the Atlantic salmon (Salmo salar) were examined by electron microscopy at three stages of this process, which were defined as follows: "parrs" were freshwater fish that had not yet started their transformation; "freshwater smolts" were freshwater fish that were ready to enter seawater; and "seawater smolts" were smolts that had been transferred from fresh water and maintained for 4 days in seawater (35%). In the gill epithelium of parrs, there were two types of chloride cells. The large chloride cells contained deeply stained mitochondria and numerous apical, irregular, dense, membrane-bound bodies that formed 77% of the chloride cell population and were distinguished easily from small chloride cells that have distinctly paler mitochondria and no dense bodies in their apical cytoplasm. In freshwater smolts, the large chloride cells formed 95% of the chloride-cell population. In contrast to the small chloride cells that were not modified, they almost doubled in size. Their tubular system developed extensively to form a tight network with regular meshes significantly smaller than those observed in parr chloride cells. Forty percent of the large chloride cells were associated with a new type of cell, the accessory cell, to which they were bound by shallow apical junctions. Half of these accessory cells were not seen to be in contact with the external medium. In seawater smolts, 80% of the large chloride cells were associated with accessory cells. Most accessory cells reached the external medium and sent numerous cytoplasmic interdigitations within the apical portion of the adjacent chloride cells. As a result, a section through the apical portion of the chloride cells and their associated accessory cells revealed a mosaic of interlocked cell processes bound together by an extended, shallow apical junction. It was concluded that the Atlantic salmon develops in fresh water most of the ultrastructural modifications of the gill epithelium which in most euryhaline fish are triggered by exposure to seawater. The effective transfer into seawater would act only as a final stimulus to achieve some adequacy between the freshwater smolt and its new environment.

Impact of detergents on the protein histochemistry of various cell types of the gill epithelium of Rita rita.

Fish, Rita rita, were exposed to an anionic detergent, dodecylbenzene sodium sulfonate, 6.9 mg per litre of tap water (96-hr LC50 of the detergent). A gradual decrease in the protein constituents of the major cell types, viz, the epithelial cells and the goblet mucous cells in the epithelium lining the gill arch, gill filament, and club cells present only in the gill arch epithelium has been observed by using a series of histochemical techniques.

Comparative activity of gill ATPase in three freshwater teleosts exposed to cadmium.

The comparative activity of gill ATPase was examined in the bluegill sunfish (Lepomis macrochirus), fathead minnow (Pimephales promelas), and golden shiner (Notemigonus crysoleucas). Basal Na/K ATPase activity was highest in bluegill sunfish (1.46 mumol Pi/mg protein/hr) and lowest in golden shiners (1.01 mumol Pi/mg protein/hr). While a stimulation of Na/K ATPase activity was observed at an exposure concentration of 1 micrograms Cd/liter in the bluegill sunfish and fathead minnows, an inhibition of enzymatic activity was observed at higher exposure concentrations (10 and 100 micrograms Cd/liter). Gill Na/K ATPase activity in golden shiners was not significantly influenced by cadmium exposure. The observed insensitivity of Na/K ATPase in golden shiners may, in part, be related to high background concentrations of cadmium in gill tissue. In all three species examined, gill residual ATPase activity was not significantly altered by cadmium exposure.

Light microscopic characterization of glycoconjugates in secretory cells of the carp (Cyprinus carpio) gill epithelium.

Secretory products of granular and mucous cells in the gill epithelium of the carp, Cyprinus carpio, were distinguished by their cytochemical reactions with peroxidase-labelled lectins and with the galactose oxidase (GO)-Schiff reagents. Secretory products of granular cells reacted with lectins from Triticum vulgaris (WGA), Arachis hypogaea (PNA), Dolichos biflorus (DBA), Glycine max (SAB), and Lotus tetragonolobus (LTA). They also reacted with GO-Schiff reagents. After sialic acid cleavage with HCl, new binding sites for DBA and SBA appeared, suggesting the terminal sequence sialic acid-N-acetylgalactosamine (SA-GalNAc) for the secretion of this cell type. In mucous cells, binding sites for WGA, DBA, and SBA and, after acid hydrolysis, binding sites for PNA and a positive GO-Schiff reaction were detected. The terminal trisaccharide sialic acid-galactose (beta 1-3)-N-acetylgalactosamine (SA-Gal-GalNAc) is proposed for the secretion of mucous cells. These cytochemical differences are discussed in light of the involvement of both cell types in fish mucus elaboration.

Biological monitoring of heavy metal pollution in the region of Lake Balaton, (Hungary).

The concentrations of toxic heavy metals (Hg, Cd, Cr, Cu, Zn and Pb) were measured by atomic absorption spectrophotometry in the gills of mussels (Unio pictorum L.) both living in Lake Balaton as well as transferred to various parts of tributaries of the Lake. The measurements were performed separately with two-week intervals during the course of several months. It was found that (1) the concentration of the studied metals varied with time at each location, less variation occurred in the mussels living in the Lake itself. (2) There were both increases and decreases in the heavy metal concentration of the gills, presumably reflecting the changing level of pollution of the water. It is concluded that mussels can be used as biological indicators for detecting temporal variations in the degree of toxic heavy metal contamination in surface waters, and are good objects for signalizing local events of pollution.

The cellular location of 1 alpha-hydroxycorticosterone binding protein in skate.

Antiserum to 1 alpha-hydroxycorticosterone binding protein was used to investigate its location in selected tissues of the skate Raja ocellata. Immunofluorescence, using an indirect technique, showed 1 alpha-hydroxycorticosterone binding sites in potential target tissue: gill. chloride cells, rectal gland parenchyma, and a portion of the kidney tubule. The binding protein was not detectable in the ventricle or the intestinal spiral valve but was associated with liver parenchyma and interrenal cells. The intracellular location of the binding protein is apparently tissue specific.

Cadmium in edible crabs (Cancer pagurus L.) from Scottish coastal waters.

Concentrations of cadmium in the hepatopancreas (0.1-61.3 mg kg-1), gonad (0.15-11.0 mg kg-1) and gills (0.2-10.7 mg kg-1) of the edible crab Cancer pagurus L. from 16 sampling sites round the Scottish coast are reported, and compared with published elevated concentrations in crabs from the Orkney Islands. Geographical variations in the distribution of cadmium between organs indicate that the dietary uptake of cadmium is predominant in northern mainland and Orkney crabs, but that uptake from the water is more important in the south of Scotland. Mean dissolved cadmium concentrations in eastern coastal water increase from approximately 10 ng dm-3 in northern waters to approximately 25 ng dm-3 in the south. It seems likely that a regional contamination of the environment by cadium of geological origin occurs in the extreme north coast of Scotland, and in the Orkney and Shetland areas.

Adrenergic innervation of the gills, pulmonary arterial plexus, and dorsal aorta in the neotenic salamander, Ambystoma tigrinum.

The presence of adrenergic innervation was investigated in four different vascular segments of the neotenic tiger salamander, Ambystoma tigrinum, by histofluorescent staining for catecholamines. The segments were the respiratory section of the gill, the branchial shunt vessels, a vascular plexus in the pulmonary artery, and the dorsal aorta. No adrenergic fibers were detected in the respiratory section of the gill or the pulmonary arterial plexus. In contrast, the branchial shunt vessels contained both adrenergic varicosities and catecholamine-containing cell bodies. These cells resemble Type I cells of the mammalian carotid body and amphibian carotid labyrinth. Adrenergic innervation of the dorsal aorta was sparse and restricted to the adventitia. The results suggest that adrenergic nerves may directly regulate blood flow in the gill, and thus gas exchange, by controlling vascular resistance of the branchial shunts. The contractile state of the dorsal aorta may also be under adrenergic control. In addition, it is suggested that the adrenergic cells of the branchial shunts may serve a receptor function in being sensitive to arterial blood gases.

Ultrastructural changes in gills of Sarotherodon mossambicus treated with chicken manure.

Sarotherodon mossambicus were fed a chicken manure (60%) supplementary diet for 4 weeks under laboratory conditions, and significantly higher (P less than 0.05) concentrations of Mn, Fe, Cu, Pb, and Zn were obtained in the gills of the treated fish. Ultrastructural changes including separation of the epithelium from the pillar cell system and subsequently increasing the blood-water barrier, necrosis of lamellar cells, collapse of lamellar blood spaces, and hyperplasia of interlamellar cells were found in the lamellae of the gills of the treated fish.

Complexity of nuclear and polysomal RNA from squid optic lobe and gill.

The sequence complexity of nuclear and polysomal RNA from squid optic lobe and gill was measured by RNA-driven hybridization reactions with single-copy [3H]DNA. At saturation, brain nuclear and polysomal RNAs were complementary to 22.8 and 7.9% of the DNA probe, respectively. Assuming asymmetric transcription, the complexity of nuclear and polysomal RNA was equivalent to 2.5 X 10(8) and 8.8 X 10(7) nucleotides, respectively. Approximately 80-85% of the sequence complexity of brain total polysomal RNA was found in the polyadenylated RNA fraction. In contrast to these findings, nuclear and polysomal RNAs from gill hybridized to 9.1 and 2.9%, respectively, of the single-copy DNA, values that were 2.5-fold lower than those obtained in the CNS. Taken together, the results focus attention on the striking diversity of gene expression in the squid CNS and extend to the cephalopod mollusks the observation that nervous tissue expresses significantly more genetic information than other somatic tissues or organs.

Determination of the phospholipid composition of trout gill by Iatroscan TLC/FID: effect of thermal acclimation.

The phospholipid composition of gill tissue from thermally acclimated rainbow trout, Salmo gairdneri, was determined by Iatroscan analysis following an initial development of the chromarods in a non-polar solvent to remove neutral lipids. Standard curves for all phospholipids, although linear through most of the concentration range tested (1-40 micrograms), extrapolated to negative intercepts on the ordinate, indicating a decline in sensitivity at low phospholipid levels. In addition, the concentration dependence of the Iatroscan response varied by nearly 6-fold among phospholipids. Of the major phospholipids, only lysophosphatidylcholine could not be quantitated accurately because of the presence of an interfering peak. Quantitation by Iatroscan yielded results which, in general, agreed well (within 5%) with results obtained by an independent phosphate analysis. Only in the case of phosphatidylinositol (PI) did the two analytical methods differ significantly; proportions of PI were 55% higher when determined by Iatroscan as opposed to phosphate analysis. Gill tissue from 5 C-acclimated trout possessed higher proportions of phosphatidylethanolamine than tissue from 20 C-acclimated trout. The Iatroscan provided a rapid and reliable means of quantitating the proportions of all the major phospholipids of trout gill, although there are some limitations to the general applicability of the technique.

The effect of certain antibiotics on the keeping quality of bolti fish (Tilapia nilotica).

Fresh bolti fish (Tilapia nilotica), caught in the river Nile was immersed in 10 and 20 ppm tetracycline (TC) solutions for 10 and 15 min respectively and in 500 and 1000 R.U. nisin/g fish for 20 and 30 min respectively. Total volatile bases (TVN) showed in both fish treated with TC and nisin a slow increase at the first stage and after that a fast increase. There was an increase in trimethylamine (TMA) during the storage period, but the fish treated with TC and nisin contained less TMA than the control. Starting from 6 h the residual TC decreased gradually till the third day, when it disappeared completely. There is no change in pH values in both control and treated fish. Optical density (OD) of gills extract increased gradually as the storage period progresses. The treated fish showed lower OD values than the controls. The refractive index of muscle fluids and the OD of muscle extract showed no significant differences between the control and treated fish.

Plasmalogens in the gill lipids of aquatic animals.

Lipids constituted 0.6-2.2% wet wt of the gills of 11 species of aquatic animals (4 bivalves, a crustacean and 6 fishes). Phospholipids, largely phosphatidylcholine (PC) and phosphatidylethanolamine (PE), are major components of all species. The plasmalogen contents of these lipids were 47-291 mumol/g, with the highest values found for bivalve gill total lipids and the catfish phospholipid fraction.

Changes in the fatty acid composition of phospholipids from turbot (Scophthalmus maximus) in relation to dietary polyunsaturated fatty acid deficiencies.

Young turbot (1-20 g) were maintained for not less than 14 weeks on three diets: (1) a control diet containing normal amounts of polyunsaturated fatty acids (PUFA); (2) a diet totally deficient in PUFA; (3) a diet deficient in the (n-6) series of PUFA but containing (n-3) PUFA. At 14 weeks the fatty acid compositions of the phospholipids from liver, gut, gills and muscle were analysed. Large changes in the amounts of PUFA in the phospholipids were found. Fish maintained on the totally PUFA deficient diet 2 had retained arachidonic acid, 20:4(n-6), and docosahexaenoic acid, 22:6(n-3), at the expense of eicosapentaenoic acid, 20:5(n-3). Fish maintained on the (n-6) PUFA-deficient diet (3) contained decreased amounts of 20:4(n-6) and 22:6(n-3) while retaining 20:5(n-3). In all cases phosphatidylinositol had the lowest n-3/n-6 ratios. These results are discussed in terms of PUFA function.

The cytoskeleton of the apical border of the lateral cells of freshwater mussel gill: structural integration of microtubule and actin filament-based organelles.

The coexistence of densely packed microtubule- and microfilament-based elements in the apex of ciliated epithelial cells, such as the lateral (L) cells of freshwater mussel gill, suggests that with this system it may be possible to define structural connections and interactions that permit integrated cytoskeletal responses to known physiological stimuli. In this study we examine the structure of the L cell apex in detail. The central elements of the elaborate cytoskeleton of the cortex are the basal bodies whose specialized accessory processes are points of integration and the focus of cortical microtubule and microfilament networks. Each basal body supports a cilium and interacts with adjacent basal bodies and with the cell periphery via a dual set of fibre-containing flat trabeculae, both of which are attached to a special organizing centre, the basal foot cap. The distal trabecula is composed of microtubules and the proximal of microfilaments. Connecting the trabeculae, at vertices in the filamentous grids, are core bundles of microfilaments from apical microvilli. In this way, a zig-zag pattern that characterizes microvillar organization at the cell surface is generated. At the cell periphery, the microfilaments from basal foot caps join a peripheral band of microfilaments that underlies the cell border and is associated with four special sites, one in each corner of the cell. Mussel gill epithelial cells contain a polypeptide that resembles actin in its mobility in sodium dodecyl sulphate/10% (w/v) polyacrylamide gels and its affinity for DNase I. Decoration with heavy meromyosin demonstrates that many microfilaments of the L cell apex contain actin, including the microvillar core and peripheral band microfilaments. Actin-associated proteins are also present in these epithelial cells. The actin filaments of the peripheral band are organized to support contraction of the cell border, which would also affect each element of the cortex. This structural complexity, combined with the limited number of modes of interaction between various elements, suggests that the L cell apical cytoskeleton endows the cell with significant positional and morphogenetic information that could be used to compute organellar and cytoskeletal lengths, spacing and changes upon stimulation.

Hemocyte lysate enhancement of fungal spore encapsulation by crayfish hemocytes.

Crayfish hemocytes exhibited a stronger encapsulation reaction to fungal blastospores of Beauveria bassiana coated with hemocyte lysate, than to blastospores treated with plasma or buffer, indicating an opsonic function of hemocyte lysate proteins. Five proteins of the prophenoloxidase activating system in the hemocytes were attached to foreign surfaces (including the blastospores) after activation and it is suggested that these attaching proteins (one being phenoloxidase) are responsible for the opsonic function of the hemocyte lysate on crayfish blood cells.