Rainbow trout (<I>Oncorhynchus mykiss</I>) gill was found to generate three main lipoxygenase products, namely 12-hydroxyeicosatetraenoic acid (12-HETE), 12- hydroxyeicosapentaenoic acid (12-HEPE) and 14-hydroxydocosahexaenoic acid (14-HDHE) and to a lesser extent a single identifiable dihydroxy product, 8, 15-dihydroxyeicosatetraenoic acid (8,15-diHETE). All four compounds were structurally elucidated by gas chromatography-mass spectrometry. Variation in the eicosanoid profile was observed with respect to 12-HETE and 8,15-diHETE generation in density gradient centrifugation fractionated gill cells. In fish, eosinophilic granule cells (EGCs) have been considered to be equivalent to mast cells known to occur in all other vertebrate classes. These cell types share a number of common features including connective tissue distribution and degranualting behaviour, although equally, there are important differences. From the present study, the numbers of EGCs found in rainbow trout gill explant cultures following incubation with lipopolysaccharide (LPS) and tumour necrosis factor-α (TNF-α) increased significantly, suggesting that cytokines may mediate the differentiation and development of EGCs. Similarly, induction of fish stress by modification of environmental parameters appeared to cause an increase EGC accumulations in the gill. The discovery of the inducible cyclooxygenase enzyme (COX-2) in mammals came from initial studies examining the stimulated prostanoid generation in the presence of mitogens and hormones. Subsequently, specific drugs and antibodies have been developed allowing the clarification of inducible COX activity in a wide variety of cells and tissues. Fish macrophages, similarly generate increased amounts of prostaglandin E when stimulated with macrophage-derived factors and/or bacterial LPS, a response found to be inhibited by the COX-2 specific inhibitor, NS398, and by dexamethasone and cyclohexamide. These results imply the existence of an inducible COX activity in fish potentially homologous to mammalian COX-2.

<U>Melittobia acasta </U>Walker is a parasitoid of many insect species distributed in several families among which is the Calliphorinae. In this study, its reproductive behaviour and interactions with one of its hosts, <U>Calliphora</U> species puparia, were examined. The courtship behaviour pattern of <U>M. acasta</U>, which is innate, is described. Unlike other parasitoids, such as <U>Nasonia vitripennis</U> Walker, copulation occurs within the host puparium before emergence. The females in this species are more active that the males and assume the role of chasing males during mate location. Although the males are mutually antagonistic, fighting on making contact with each other, they do not decapitate the loser in fight as previously described by many workers. Where several females are present within a puparium, males ignore each other, preferring mating activity. Host finding is random. After finding a puparium, the female taps it on the outside with the antennae and abdomen, then decides whether the pupa inside is acceptable for oviposition. If it is, the female drills into the puparium with the ovipositor, probes the host and then lays eggs on the pupa within the puparium. Two types of drilling were noticed; drilling for food and drilling for egg laying. Most of the drillings were at the intersegmental notches of the puparium. <U>Calliphora</U> sp. puparial age and size had a significant effect on the parasitoid's clutch size and sex ratio but no effect on the development time, order of male/female egg laying and size of parasitoids emerging from the puparium. The ovipositing females preferred living, envenomed, non-diapausing puparia to dead, unvenomed or diapausing ones. The sense organs on the antennae and ovipositor that aid the parasitoid in assessing and utilising <U>Calliphora</U> sp. puparia are described.

No description available.

This study is an investigation into the non-specific immune systems of bony and cartilaginous fish. Rainbow trout (<i>Oncorhynchus mykiss)</i> head kidney macrophages were incubated with zymosan particles (opsonized in normal trout serum) and the extent of phagocytosis was compared with that of non-opsonised particles. Long-term exposure of these macrophages to purified complement factor C3a-1 resulted in the enhanced generation of prostaglandin E₂ (PGE₂) that was confirmed using gas chromatography-electron capture mass spectrometry and quantified using enzyme immunoassay. In initial studies, the enhanced generation of PGE₂ was found to be due to the upregulation of cyclooxygenase-2 using RNA extraction and reverse transcription-polymerase chain reaction analysis. Histological sections of muscle, oesophagus, spleen gonad, liver, intestine and gill from the Thornback ray, <i>Raja clavata</i> were examined and areas of haemopoiesis highlighted. The principal sites of haemopoiesis were in the gonads and oesphagus. All tissues were found to generate PGE and several lipoxygenase products. Five of these products were identified as 6-<i>trans-</i>leukotriene (LT)B₄, 6-<i>trans</i>-12-epi-LTB₄, 8-15 dihydroxyeicosttetraenoic acid (HETE), 15-HETE and 15-hydroxyeicosapentaenoic acid (HEPE). No LTB₄ generation was observed. Incubation of oesophageal leucocytes with authentic LTA₄ did not result in the generation of LTB₄, suggesting the absence of LTA₄ hydrolase. Initial studies of the natural humoral antibacterial activity of serum from rays <i>(R. clavata)</i>, dogfish (<i>Scyliorhinus canicula)</i> and trout, and of dogfish leucocytes and trout thrombocytes were carried out using a microtitre plate based killing assay against several species of bacteria. Variable levels of antibacterial activity were found in these samples although the reproducibility of this method was questioned. Lysozyme-like activity in serum from rays and dogfish, and in the leucocytes of dogfish and thrombocytes of trout was also quantified. In particular the thrombocytes were found to contain lysozyme-like activity in significant amounts suggesting a role for these cells in antibacterial defence.

On exposure to the atmosphere at low tide, bivalve molluscs avoid desiccation by shell closure, which can result in hypoxic conditions within the mantle cavity. Thus, these animals may exhibit an anaerobic pattern of metabolism during tidal exposure. However, during exposure to the atmosphere, the four species of bivalve molluscs (Mytilus edulis, Cardium edule, Scrobicularla plane and Macoma balthica) investigated were found to be able to incorporate atmospheric 14C02 into their tissues. It is suggested that the accessibility of atmospheric 14CO2 into the interior of these animals during exposure argues that atmospheric oxygen is also accessible to the interior and that these animals are not normally completely anaerobic during exposure to the atmosphere. Significant seasonal changes in the metabolism of 14C02 by tissues of M. edulis were observed. It is argued that these changes are due to seasonally-dependent changes in the energy reserve and not to differences in temperature. However, experimentally induced changes in temperature were found to reinforce the succinate pathway. Experiments designed to measure the metabolism of 14C02 by M. edulis, C. edule and S. plane e- under various environmental conditions (aerobic, anaerobic exposed and buried) indicate clear species differences. The results are discussed in relation to the ecological distribution of each species. C. edule was observed to be independent of the succinate pathway during exposure. This independence was not seasonally linked. However, S. plane utilised the succinate pathway during exposure to the atmosphere and the extent-62f such utilisation is subjected to significant seasonal changes. A comparative study on the metabolism of 14C02 by the four species of bivalve molluscs suggests that the pattern of incorporation is dominated by species differences. Significant tissue differences were also observed. The effect of temperature on the kinetics of the enzyme pyruvate kinase from the adductor muscle of M. edulis was examined. It is suggested that the succinate pathway operates not only during hypoxia, but also in response to stressful situations.

No description available.

No description available.

The blood cells of the common blue mussel <i>Mytilus edulis</i> have been characterized using a range of criteria including, electron microscopy, lectin-affinity and enzyme localization. Three distinct sub-populations of haemocyte have been identified; these can be characterized on the basis of ultrastructural morphology as small agranular cells, granular cells containing small granules and granular cells containing large granules. Lectin-binding studies have shown the small granules of the granular cells to be positive for <i>Helix pomatia</i> lectin (HPA) indicating the presence of N-acetyl-α-galactosaminyl residues within the granules. The larger granules were not positive for HPA but did bind wheat-germ agglutinin (WGA) which has an affinity for N-acetyl-β-glucosaminyl residues and N-acetyl-β-D-glucosamine oligomers. Furthermore the WGA-positive granules demonstrated a differential pattern of binding according to granule size, so that peripheral labelling was observed for granules of around 0.5 μm diameter whereas labelling occurred throughout the matrix for granules over 1 μm diameter. The lectin binding studies also demonstrated binding of both HPA and WGA as well as <i>Tetragonolobus purpureas</i> lectin( TPA) to the plasma membrane of a number of haemocytes; however the results did not demonstrate any correlation between surface lectin binding and cell type, as defined by the ultrastructural morphology. A range of hydrolytic enzymes was localized in association with the large granules of the granular cells, these included arylsulphatase, β-glucuronidase, elastase, lysozyme and cathepsin B, indicating that these granules constitute a form of lysosome. The small granules contained protease enzymes and in particular cathepsin G antibodies showed a high affinity for these granules.

Using hybridoma technology, six monoclonal antibodies (mAbs) against a serum lectin designated BDL1 from the cockroach, <I>Blaberus discoidalis</I>, were produced and characterised. These antibodies, namely, 1G12, 1H4, 3B1, 6B4, 11E1, 13E10, were isotyped as IgG1. Immunoaffinity chromatography using purified mAbs against BDL1 immobilised on CNBr-activated Sepharose 4B matrix was successfully employed to purify BDL1 from the serum of the cockroach, <I>Blaberus dicoidalis</I>. BDL1-like lectins were also detected in the sera of two other cockroach species, namely, <I>Blaberus craniifer</I> and <I>Gromphadorhina portentosa</I>, and were purified by immunoaffinity chromatography. BDL1 and BDL1-like lectins purified by immunoaffinity chromatography have molecular masses of <I>ca</I>. 65 kDa and 32 kDa under non-reducing and reducing conditions, respectively. Immunocytochemistry with mAbs demonstrated that BDL1 is present in the haemocytes of <I>B. discoidalis</I>. Its presence in the haemocytes was further confirmed by Western blotting. BDL1 was not found in other tissues such as fat body, Malphigian tubules, midgut, testis and ovary. Immunocytochemical staining also showed that BDL1-related components are present in the haemocytes from several other cockroach species, namely, <I>Blaberus craniifer, Gromphadorhina portentosa, Periplaneta americana, </I>and <I>Leucophaea maderae</I>. Immunoaffinity purified BDL1 was found to agglutinate a range of animal erythrocytes as well as bacteria and yeast <I>in vitro</I>. It also enhanced the phagocytosis of of nonself particles including rabbit erythrocytes, <I>E. coli</I> and the baker's yeast <I>Saccharomyces cerevisie</I> by the plasmatocytes of the cockroach, <I>Blaberus discoidalis</I>, in an <I>in vitro</I> phagocytosis assay. In addition, BDL1 enhanced the activation of prophenoloxidase system by laminarin. All these results indicate that BDL1 is a multifunctional factor in the haemolymph of the cockroach, <I>Blaberus discoidalis</I>, and plays important roles in the immune responses of this insect.

The toxic effects of three individual petroleum hydrocarbons - benzene (aromatic), cyclohexane (alicyclic) and hexane (aliphatic) - on different species and life stages of marine invertebrates were investigated. For the larval stages, the trochophore larvae of the tubicolous polychaete Pomatoceros triqueter were found to have the lowest tolerance. It was seen that these compounds depress the ability of sperm to fertilize eggs and cause damage to the cytoplasm and cell membrane of both fertilized and unfertilized eggs. Sperm are less sensitive than eggs. The effects were directly correlated with the concentration applied. The resistance of these developmental stages to the effects of hydrocarbons increases with advancing age, so that adult worms are more resistant than 7-day old trochophore larvae, while developing trochospheres are the most sensitive stages. Low concentrations of toxicants had little effect on growth rates. Hexane seems less toxic, while there was no significant difference between the toxicity of benzene and that of cyclohexane.