bluuebunny/crossref_metadata_2025 huggingface dataset:
The immunomodulatory effect of LPS, laminaran and sulphated laminaran [β(l,3)‐D‐glucan] on Atlantic salmon,Salmo salarL., macrophagesin vitro
Authors: DALMO R. A. , SELJELID R.
Published: April 2006

Abstract.The stimulatory effect of LPS (Vibrio anguillarum), laminaran and sulphated laminaran, aqueous soluble β(1,6)‐branched β(l,3)‐D‐glucan obtained fromLaminaria hyperborea, on head kidney macrophages of Atlantic salmon,Salmo salarL., is reported. The macrophages, after stimulation with LPS or laminaran, showed pronounced spreading, membrane ruffling and increased organellc content when examined by light microscopy. LPS stimulation induced enhanced phagocytic and pinocytic activity, higher intraccllular production of superoxide anion, and higher activity of acid phosphatase compared to control cells. Native laminaran stimulated the cells to pinocytose more fluid phase, increase the intracellular production of superoxide anion and to elevate the activity of acid phosphatase. Sulphated laminaran induced higher production of superoxide anion and higher activity of acid phosphatase by macrophages than in control cells.
Herpesviral haematopoietic necrosis of goldfish, Carassius auratus (L.)
Authors: JUNG S. J. , MIYAZAKI T.
Published: April 2006

Abstract. In the spring of 1992 and 1993, an epizootic with severe mortality occurred among cultured goldfish. Carassius auratus (L.), in Aichi and Nara Prefectures in Japan. A herpes‐virus was isolated from moribund goldfish that induced cytopathic effects in FHM and EPC cells. The isolate was sensitive to IUdR (5‐iodo‐2‐deoxyuridine), acid (pH 3) and ether. Transmission studies confirmed the pathogenicity of the viral isolate for goldfish while it was not pathogenic for fancy carp, Cyprinus carpio L. Diseased fish had no visible external signs except for listlessness, but internally there was softening and discolouration of the spleen and kidney, and necrotic foci in the haematopoietic tissue, splenic pulp, pancreas, and lamina propria and submucosa of the intestine. Electron microscopy revealed enveloped visions ranging from 170 to 220nm in diameter with hexagonal nucleocapsids (115–117nm edge‐to‐edge diameter). The disease has been designated as herpesviral haematopoietic necrosis (HVHN), and to date, is the only herpesvirus infection to be described in goldfish.
Glycogen, the preferred energy source for extracellular protein formation and growth of Aeromonas salmonicida
Authors: COLEMAN G. , COLLIGHAN R. J. , DODSWORTH S. J.
Published: April 2006

Abstract. A study was made of the effect of supplementing a rich 3% (w/v) tryptone soya broth (TSB) medium and a poorer 1.7% (w/v) tryptone‐based medium with glucose, maltose and glycogen, as carbon sources, on growth and exoprotein formation by Aeromonas salmonicida. In TSB, glucose inhibited growth and repressed exoprotein formation whilst maltose and glycogen had little effect, up to 20h, when compared with an unsupplemented control. By contrast, in the poorer medium, over a 24‐h incubation period, growth was stimulated three‐fold by glycogen, and whilst exoprotein formation was low in comparison with that observed in TSB, the greatest production was observed in the presence of glycogen. Extracellular α‐amylase was measured in the tryptone medium in the presence of the three carbon sources and the highest level, produced in the presence of glycogen, was 1.6 times that with added maltose whilst none was detectable with glucose present. This pattern was repeated in the case of the maltose‐inducible porin, LamB, of the outer membrane.
Virulence of Flavobacterium branchiophilum in experimentally infected salmonids
Authors: OSTLAND V. E. , MacPHEE D. D. , LUMSDEN J. S. , FERGUSON H. W.
Published: April 2006

Abstract. The ability of selected strains of Flavobacterium branchiophilum to attach to and colonize the gills of five species of teleosts (four salmonid and one cyprinid) and cause mortality was investigated. In virulence studies with F. branchiophilum strain LAB4a, cumulative mortality was dose‐dependent in rainbow trout, Oncorhynchus mykiss (Walbaum), and ranged from 0 to 75%. However, regardless of dose, the relative amount of gill‐associated F. branchiophilum antigen increased 1 h after challenge. The gill‐associated F. branchiophilum antigen in fish which survived (moribund fish) increased by four to six times compared to that detected on the gills 1 h after challenge. The gill‐associated antigen on moribund fish was not significantly different from that on the gills of dead fish. Flavobacterium branchiophilum strain LAB4a also attached to the gills of brook trout, Salvelinus fontinalis (Mitchell), rainbow trout, chinook salmon, Oncorhynchus tshawytscha (Walbaum), Arctic charr, Salvelinus alpinus (L.), and common shiners, Luxilus cornutus (Mitchell), following a 1‐h bath exposure, and caused mortality in all species. The virulence of eight strains of F. branchiophilum for rainbow trout was examined. Both virulent and avirulent strains adhered to the gills following bath exposure (fimbriae were observed on all strains), but only virulent strains had the capacity to further colonize the gills and cause mortality.
Partial purification and characterization of extracellular metalloproteases from Aeromonas salmonicida ssp. salmonicida
Authors: ARNESEN J. A. , EGGSET G , JØRGEN SEN T. Ø.
Published: April 2006

Abstract. Aeromonas salmonicida ssp, salmonicida is shown to produce several extracellular proteins having gelatinolytic activity. Among the six isolates tested, two (NCMB 1102 and 84–14–R) produced both high (89–100 kDa) and low molecular (37 kDa) weight gelatinases, while the other four demonstrated only the 89–100 kDa forms. The low molecular form (metalloprotease 1: MP 1, 37 kDa) was isolated by ammonium sulphate precipitation, hydrophobic, ion exchange and size exclusion chromatography. The isolated enzyme was inhibited by the metal‐chelating agents o‐phenantroline and EDTA, and by excess Zn ions, and thus was defined as a metalloprotease. Its pH‐optimum was 7–5, optimal activity was at 40°C and its pI 5.2. Specificity studies demonstrated cleavage of gelatin and azocoll, but not casein.
Antioxidant status and immunity in Atlantic salmon, Salmo salar L., fed semi‐purified diets with and without astaxanthin supplementation
Authors: CHRISTIANSEN R. , GLETTE J. , LIE ø. , TORRISSEN O. J. , WAAGBø R.
Published: April 2006

Abstract. Parr of Atlantic salmon, Salmo salar L., were fed semi‐purified diets supplemented with 60 mg astaxanthin kg−1 and without astaxanthin supplementation for 10.5 months. The astaxanthin concentration in the non‐supplemented diet was analysed to be 6–0 mg kg−1 The growth of the fish was significantly affected by the dietary treatment. The mean daily weight gain in the groups fed the supplemented diets was 0.39% throughout the period, whereas the groups fed the non‐supplemented diet had a mean daily weight gain of 0.18%. The dry matter and fat content were significantly higher in fish fed the supplemented diet. The astaxanthin concentration in the muscle of fish fed the astaxanthin‐supplemented diet was 2–7 mg kg−1 versus 0–3 mg kg−1 in the non‐supplemented fish. Antioxidant vitamins in the muscle (retinol, α‐tocopherol) and liver (retinol, α‐tocopherol and ascorbic acid) were two to 20 times higher in the fish in the supplemented group, suggesting antioxidant sparing effects. Blood haemoglobin and immunological parameters tended to be higher in fish fed the low astaxanthin diet although the difference was not significant. However, the resistance to challenge with Aeromonas salmonicida was higher in fish fed the astaxanthin supplemented diet. This may be due to a difference in weight at the time of the challenge which, in turn, may have influenced the body composition and smoltification of the fish. A relationship between dietary astaxanthin concentration and antioxidant status in both liver and muscle was observed, and this may also have had an influence on the observed differences in blood parameters and disease resistance.
Relevance of Renibacterium salmoninarum in an asymptomatic carrier population of brook trout, Salvelinus fontinalis (Mitchill)
Authors: STARLIPER C. E. , A J. D. TESK
Published: April 2006

Abstract. These studies were done to determine the prevalence of infection, over time, of progeny from a population of 1988 year class brook trout, Salvelinus fontinalis (Mitchill), that was asymptomatically infected with Renibacterium salmoninarum, the causative agent of bacterial kidney disease. This population and its progeny from the 1991 and 1992 spawnings were monitored for approximately 3 years for prevalence of R. salmoninarum and development of bacterial kidney disease. Ovarian fluid samples from the 1991 and 1992 spawnings, and from a 1993 spawning of the 1991 progeny, were analysed for R. salmoninarum by enzyme linked immunosorbent assay (ELISA) and the membrane filtration fluorescent antibody technique. Kidney and spleen tissues of the 1988 year class were assayed by ELISA following the 1992 spawning. The progeny of the 1991 and 1992 spawnings were followed for increased prevalence of R. salmoninarum by the ELISA. Kidney tissues were assayed and sampling began once the fish were large enough. Each population of progeny was sampled quarterly for one year. Overall, the progeny displayed decreasing prevalence of R. salmoninarum and all ovarian fluids of the 1991 progeny (in 1993) were negative. Brood fish and progeny remained asymptomatic during the course of the study.
Loxothylacus ihlei Boschma, (Rhizocephala) and its effects on the mud crab, Scylla serrata (Forskål), in northern Australia
Authors: KNUCKEY I. A. , DAVIE P. J. F. , CANNON L. R. G.
Published: April 2006

Abstract. Loxothylacus ihlei, a rhizocephalan parasite of the mud crab, Scylla serrata (Forskål), is reported for the first time in Australian waters. The parasite is described and found to be variable in a number of characters. Most infected S. serrata, collected from commercial catches in the Northern Territory, Australia, were significantly smaller than uninfected crabs, and their abdominal flaps were relatively larger than those of mature females. Annual prevalence of infection was low (2.1%), with the monthly variation ranging from negligible early in the year to around 7% in November.
Interaction of the fish pathogen Aeromonas hydrophila with tilapia, Oreochromis aureus (Steindachner), phagocytes
Authors: LEUNG K. Y. , LOW K. W. , LAM T. J. , SIN Y. M.
Published: April 2006

Abstract. Interaction of Aeromonas hydrophila and tilapia, Oreochromis aureus (Steindachner), phagocytes was studied in vitro. All virulent and avirulent strains of A. hydrophila tested could multiply in non‐activated and Freund's complete adjuvant activated phagocytes. Activated phagocytes increased the uptake of bacteria into cells, and the rates of intracellular replication for these bacteria were faster than in non‐activated phagocytes. Among the A. hydrophila strains examined, virulent strain PPD134/91 replicated at the fastest rate inside phagocytic cells and produced cytopathic effect in the phagocytes in the shortest incubation time. Opsonized avirulent A. hydrophila were sensitive to phagocyte‐mediated killing or unable to grow in phagocytes. Serum components and phagocytes may together prevent the growth of avirulent A. hydrophila in fish. The release of extracellular oxygen radicals during phagocytosis was examined using chemiluminescence assay (CL). Virulent strains induced CL responses but avirulent strains did not. This suggests that the virulent strains interacted with the phagocytes somewhat differently from the avirulent strains.
Molecular diagnosis of Marteilia sydneyi (Paramyxea) in Sydney rock oysters, Saccostrea commercialis (Angas)
Authors: ANDERSON T. J. , ADLARD R. D. , LESTER R. J. G.
Published: April 2006

Abstract. To prepare a diagnostic test, the polymerase chain reaction (PCR) with universal primers was used to amplify the internal transcribed spacer 1 (ITS1) of Marteilia sydneyi rDNA. A radiolabelled probe for M. sydneyi comprising putative ITS1 rDNA gave a strong signal for genomic DNA from M. sydneyi and no signal for host genomic DNA in Southern blots. A PCR to detect M. sydneyi used a forward primer designed from an internal site within the sequenced region and a reverse universal primer. It amplified a 650‐bp fragment of M. sydneyi DNA when a combination of host and parasite DNA, extracted from an infected oyster, was used as the template.
Low‐pH increases the binding of haemorrhagic septicaemia rhabdovirus to membrane phospholipids
Authors: COLL J. M.
Published: April 2006

Abstract. The rhabdovirus causing viral haemorrhagic septicaemia (VHS), a disease of coldwater fish, especially salmonids, binds to sonicated radioactively labelled membrane phospholipids [phosphatidylserine (PS), phosphatidylethanolamine (PE) and phosphatidylcholine (PC)]. The extent of binding of VHS V to membrane phospholipids is dependent on pH, occurring at physiological pH, but being maximal at about pH 5.5 and suggesting that a pH‐induced conformation] change is needed for the VHSV to maximally bind phospholipids. VHSV bound PS more effectively than either PE or PC, as demonstrated by ultracentrifugation and competition experiments.
Antibody response to crustacean ectoparasites in rainbow trout, Oncorhynchus mykiss (Walbaum), immunized with Argulus foliaceus L. antigen extract
Authors: RUANE N. , MCCARTHY T. K. , REILLY P.
Published: April 2006

Abstract. A humoral antibody response was demonstrated by ELISA in rainbow trout immunized intraperitoneally with extracts from the branchiuran ectoparasite Argulus foliaceus. A similar immunization protocol produced a higher titre response in a rabbit. Both trout and rabbit identified several antigenic components on immunoblots. ELISA and immunoblotting indicated that rainbow trout and rabbit anti‐A. foliaceus sera identified components from the parasitic copepods Lepeophtheirus salmonis and Caligus elongatus.
Accumulation of immunomodulatory laminaran [β(1,3)‐D‐glucan] in the spleen and kidney of Atlantic salmon, Salmo solar L.
Authors: DALMO R. A. , INGEBRIGTSEN K. , BóGWALD J. , HORSBERG T. E. , SELJELID R.
Published: April 2006

Abstract. The tissue distribution of 3H‐ and FITC‐laminaran in Atlantic salmon, Salmo salar L., was investigated after intravenous administration. Liquid scintillation counting and whole‐body autoradiography revealed that the concentration of 3H‐labelled laminaran in the spleen and anterior kidney was higher than in blood throughout the experimental period (1 h to 12 days). Renal excretion and intestinal exsorption were the main elimination pathways for laminaran. Microscopic examination revealed accumulation of FITC‐labelled laminaran in macrophages in kidney and spleen. In addition, endothelial cells in the kidney, spleen, liver and intestine contained the immunomodulator. Thus, these experiments show that laminaran accumulates and is retained in immunologically relevant cells in the kidney and spleen.
Chemotherapy of Cytophaga/Flexibacter‐like bacteria (CFLB) infections in fish: studies validating clinical efficacies of selected antimicrobials
Authors: SOLTANI M. , SHANKER S. , MUNDAY B. L.
Published: April 2006

Abstract. In vitro and in vivo efficacies of commonly used chemotherapeutants were determined for Cytophaga johnsonae, Cytophaga psychrophila, Flexibacter colutnnaris and Flexibacter maritimus. Treatmeat of barramundi, Lutes calcarifer (Bloch), with oxolinic acid (OA) as a bath (50 ppm) or by mouth (10 mg kg−1 body weight) resulted in serum levels above the minimum inhibitory concentration (MIC) for F. columnaris and produced significant clinical efficacy (P < 0.05). Amoxycillin (AM) was found to produce adequate serum levels against F. maritimus when used as a bath (200 ppm) or given orally (80 mg kg−1 body weight) to Atlantic salmon, Salmo salar L. and rainbow trout, Oncorhynchus mykiss (Walbaum), respectively. At these dose rates, this antibiotic was also clinically efficacious against F. maritimus (P <0.05). Trimethoprim produced more than adequate serum levels for the control of F. maritimus when given as a bath (50 ppm) or orally (10 mg kg−1 body weight). Trimethoprim was significantly more protective than AM when tested in vivo (P < 0.05). For C. johnsonae and C. psychrophila, the MIC values for OA and oxytetracycline were low, whereas that for TMP was high. Also, based on MIC values, C. psychrophila strains were more sensitive to AM and norfloxacin than C. johnsonae.
Study of the interaction between a persistent infectious pancreatic necrosis virus (IPNV) infection and experimental infectious salmon anaemia (ISA) in Atlantic salmon, Salmo salar L.
Authors: MELBY H. P. , FALK K.
Published: April 2006

Abstract. An infectious pancreatic necrosis virus (IPNV) carrier stock of Atlantic salmon parr (100 g) was divided between two tanks and inoculated experimentally with tissue homogenate containing the aetiologic agent of infectious salmon anaemia (ISA) and non‐ISA tissue homogenate (control), respectively. Plasma and kidney samples from ISA‐infected and control fish were taken twice weekly for 25 days. In the kidney samples, IPNV was quantified by a plaque assay. In plasma, anti‐IPNV antibodies were measured using an indirect ELISA. The ISA‐infection did not seem to activate the IPNV‐infection. Neither the proportion of fish with IPNV or anti‐IPNV antibodies, nor the IPNV titre or level of anti‐IPNV antibodies showed any specific trend during the study. Independently of ISA, IPNV was detected in 54 out of 132 fish (41%), while 71 out of 195 fish (36%) had plasma antibodies against IPNV. No association was found between detection of IPNV, and presence or level of anti‐IPNV antibodies in individual fish.
Experimental transmission of a salmonid Rhodococcus sp. isolate to juvenile Atlantic salmon, Salmo salar L.
Authors: SPEARE D. J. , BROCKLEBANK J. , MACNAIR N. , BERNARD K. A.
Published: April 2006

Abstract. This paper provides further characterization of a ‘Rhodocoecus’‐like pathogen of Atlantic salmon, Salmo salar L., and describes its experimental transmission. An isolate from naturally infected fish was determined to be ‘Rhodococcus’ ‐like based on its biochemical profile and from gas liquid chromatography assessment of its cellular fatty acid methyl esterase profile in comparison to a data base. This isolate was used in an infectivity trial in which Atlantic salmon juveniles received an intraperitoneal injection of known concentrations of the bacteria. Fish receiving 0.5 ml of a 109bacteria ml−1 solution developed severe peritoneal granulomatous reactions, and bacteria were recovered from the peritoneum and the kidney. In contrast to the natural disease, in which pathological changes are often most dramatic in the renal interstitium, in our study, the lesions were restricted to the injection site—the peritoneal cavity. However, in this location, the large colonies of bacteria and the nature of the host response were both characteristic of the changes noted in the renal interstitium of naturally infected fish. Lesser concentrations of injected bacteria resulted in either no or minimal pathological change, and subsequent recovery of bacteria from injected fish was poor. Horizontal transmission to non‐injected co‐habitants was not achieved.
Immunogenicity of amoebic antigens in rainbow trout, Oncorhynchus mykiss (Walbaum)
Authors: BRYANT M.S. , LESTER R.J.G. , WHITTINGTON R.J.
Published: April 2006

Abstract. Rainbow trout developed a humoral immune response against numerous antigens of sonicated amoebae which were emulsified with Freund's complete adjuvant and injected into the peritoneum. The amoebae were cultured from the gills of Atlantic salmon, Salmo salar L., affected by amoebic gill disease. Antibodies in fish sera were detected by both enzyme‐linked immunosorbent assay (ELISA) and immunoblotting. Non‐spedfie reactivity in fish serum against Escherichia coli, the bacterium used in co‐cultivation of amoebae in vitro, was removed by immunoadsorption. Results obtained using ELISA and immunoblotting were comparable and indicated no significant difference in response to immunization with 10, 50 or 250 μg of sonieatcd amoebic protein. Amoebae contained immunogenie components of > 100, 100, 89, 49, 37 and 34kDa.
Bacteria associated with early life stages of halibut, Hippoglossus hippoglossus L., inhibit growth of a pathogenic Vibrio sp.
Authors: BERGH Ø.
Published: April 2006

Abstract Bacteria capable of inhibiting growth of a pathogenic Vibrio sp. were isolated from the gastrointestinal tract of cultured halibut larvae during the first feeding and weaning stages. No such bacteria were found among isolates from the surface of eggs or the gastrointestinal tract of yolk sac larvae. The fraction of pathogen‐inhibitors among the total number of isolates ranged between 0–100% (first feeding) and 0–66% (weaning). All pathogen‐inhibitors were Gram‐negative rods, and 95% were oxidase and catalase positive fermentative isolates, capable of producing acid aerobically from a varying range of carbohydrates. These isolates possessed the characteristics of the Vibrio/Aeromonas‐group, but only 19% were sensitive to the vibriostatic agent 0/129. Isolates from eggs and yolk sac larvae were dominated by bacteria belonging to the Cytophaga/Flexibacter/Flavobacterium‐ group. The high fraction of isolates with the ability to inhibit growth of the pathogenic Vibrio sp. among the total number of isolates indicates that pathogen inhibition may be an important mutualistic role of the intestinal flora of early life stages of halibut.
Histopathology of snakehead, Channa striatus (Bloch), experimentally infected with the specific Aphanomyces fungus associated with epizootic ulcerative syndrome (EUS) at different temperatures
Authors: CHINABUT S. , ROBERTS R. J. , WILLOUGHBY G. R. , PEARSON M. D.
Published: April 2006

Abstract Snakeheads, Channa striatus (Bloch), were inoculated with a spore suspension of the specific pathogenic Aphanomyces, isolated from fish affected by epizootic ulcerative syndrome (EUS), in South East Asia. Fish were held at three different temperatures: 19, 26 and 31 °C. Histological changes induced by the infection are described. In the early stages of the disease, degenerative changes were observed in all samples, but inflammatory infiltrate was much more marked in fish kept at 26 and 31 °C. By 8 days post‐injection, extensive mycotic granulomatosis was observed in the samples kept at 26 and 31 °C. The fish kept at 19 °C developed a severe invasive myonecrosis with limited macrophage response. From 14 to 28 days post‐injection, healing became well established at 26 and 31 °C and surviving fish kept at these temperatures recovered completely by 28 days. The lesion was still progressing at 21 days post‐injection in fish kept at 19 °C, and all such fish succumbed by this time. Thus, mortalities in the fish kept at 19 °C were considerably higher than in the groups of fish kept at 26 and 31 °C. The findings help to explain why mortalities from EUS occur when water temperatures are low.
Risk factors for furunculosis, infectious pancreatic necrosis and mortality in post‐smolt of Atlantic salmon, Salmo solar L.
Authors: JARP J. , GJEVRE A. G. , OLSEN A. B. , BRUHEIM T.
Published: April 2006

Abstract An epidemiological longitudinal study comprised information obtained from 124 randomly selected Norwegian sea‐sites housing post‐molts of Atlantic salmon, Salmo salar L. Information on crude cumulative mortality, fish characteristics and farm factors was gathered by the veterinary practitioners servicing the farms. The observation period lasted from the time of sea transfer of the smolts in the spring until 1 October 1991. On average, 116480 smolts were transferred to each sea‐site. The mean crude cumulative mortality of post‐smolts during the period concerned was 16.8%. The cumulative farm‐level incidence was 54.0% for furunculosis, 39.5% for infectious pancreatic necrosis (IPN) and 10.5% for vibriosis. Occurrence of any of these specific infectious diseases in the post‐smolt was significantly associated with mortality. The risk of furunculosis was significantly related to the location of the sea site. Mixing of smolt from many freshwater hatcheries in the sea farm increased the risk of IPN significantly. In addition, the risk of IPN was related to age of site and geographic location. The mean cumulative mortality in 1‐year‐old smolt groups was 17.5%, significantly greater than in two‐year‐old fish (7.9%). In addition, the method used to transport fish from the freshwater hatchery to the sea site was significantly associated with mortality. Neither the weight of smolts at sea transfer nor the date of transfer were significantly related to mortality.
Cell‐mediated immune response of goldfish, Carassiusaurafus (L.), to Ichthyophthirius multifiliis
Authors: Sin Y M , Ling K H , Lam T J
Published: April 2006

Goldfish, Carassius auratus (L.), were intraperitoneally injected with two doses of Ichthyophthirius multifiliis (each containing 2.3 × 106 live tomites) in saline, 30 days apart. The control fish were injected with saline only. Two weeks after the last vaccination, fish of both groups were intradermally injected with 2.5 × 105 live tomites for skin tests. The skin at the antigen‐injected site of the vaccinated fish increased in thickness from 8 h onwards and reached a peak at 24 h. Histological study showed a heavy infiltration of mononuclear leucocytes at the antigen‐injected site. In contrast, no such changes were encountered in control fish. The migration area of pronephros cells from the vaccinated fish was significantly inhibited, in vitro, compared to controls with the presence of antigens. These findings suggest that the tomite‐vaccinated fish produced a cell‐mediated immune response. However, vaccinated fish also exhibited significantly higher titres of immobilizing antibodies in their sera and mucus than the controls. Therefore, it is likely that both humoral and cell‐mediated immune responses have to work closely together to eliminate the infectious tomites of I. multifiliis which succeed in penetrating the fish epithelial tissues.
Development of a nitrocellulose‐enzyme immunoassay for the detection of yellow‐head virus from penaeid shrimp
Authors: Lu Y. , Tapay L. M. , Loh P. C.
Published: April 2006

A nitrocellulose‐enzyme immunoassay (NC‐EIA) employing horseradish peroxidase (HRP) was developed for the detection of yellow‐head virus in the tissues of infected penaeid shrimp. Two substrates, DAB (3,3¢‐diaminobenzidine retrahydrochloride) and TMB (3,3¢5,5¢‐tetramethylbenzidine) for HRP were evaluated. The TMB was found to produce a more distinct and easily recognizable colour product and provided enhanced sensitivity (0.4 ng for TMB versus 0.8 ng viral protein for DAB). Under the present format, the NC‐EIA was capable of detecting as little as 100 TCID50 of virus in infected tissues. Uninfected tissue homogenates yielded no significant background colouration.
Streptococcosis in cultured turbot, Scopthalmus maximus (L.), associated with Streptococcus parauberis
Authors: Domeénech A , Derenaáandez‐Garayzábal J F , Pascual C , Garcia J A , Cutuli M T , Moreno M A , Collins M D , Dominguez L
Published: April 2006

Several strains of Garm‐positive short rod (coccibacilli)‐shaped bacteria were isolated from diseased cultured turbot, Scophthalmus maximus (L.), in the North of Spain with lesions and signs of Spain with lesions and signs of streptocecosis. The α‐haemolytic streptoceoccus‐like organisms from diseased turbot were identified by physiological, biochemical and 16S rRNA gene sequence analysis as Streptococcus parauberis. This is the first report of S. parauberis associated with fish disease.
Comparative studies of PKX and Sphaerospora spp. from salmonids using lectin and monoclonal antibody staining techniques
Authors: de Mateo M Marin , McGeorge J , Morris D , Kent M L
Published: April 2006

The results of comparative immunohisto‐chemical staining studies with two lectin probes, GS‐I and SBA, and five monoclonal antibodies raised against the PKX myxosporean are presented. In order to investigate the postulated link between PKX and Sphaerospora spp., the lectins and monoclonal antibodies were tested against PKX, Sphaerospora renicola, Sphaerospora oncorhynchi, Sphaerospora elegam, Sphaerospora truttae and Sphaero‐spora sp. from Atlantic salmon, Salmo salar L., and Ceratomyxa shasta. SBA appears a useful tool for tbe diagnosis of all Sphaerospora spp. infections and was also positive for C. shasta. GS‐I and monoclonal antibodies (12, C5, D4 and A3) appear to be specific for both the extrasporogonic and sporogonic stages of PKX. Although MabB4 was raised to PKX, it appears to stain some of the sporogonic stages of Sphaerospora spp. but not C. shasta. The results of the lectin and monoclonal staining of PKX and Sphaerospora oncorhynchi indicated that further work was required to prove or disprove the hypothesis that PKX and S, oncorhynchi are the same organism.
The postponement of non‐culturability in Aeromonas salmonicida
Authors: Pickup R W , Rhodes G , Cobban R J , Clarke K J
Published: April 2006

Aeromonas salmonicida, the causative agent of furunculosis in fish, has been shown to become non‐culturable but viable after inoculation in fresh water. The onset of non‐culturability is entirely predictable, but can be delayed by inoculation at high concentration or amendment with nutrients. This paper reports that non‐culturability can be postponed by the addition of both the amino acids methionine and arginine to microcosms inoculated with A. salmonicida. During these experiments, A. salmonicida decreased in cell size and became rounded. This was regardless of whether it received an amino acid supplement or not. We observed that cells receiving both amino acids remained culturable despite their reduction in cell size to less than 1 μm. Therefore, it would appear that the reduction in size and associated morphological change cannot be taken as an indicator of non‐culturability, although it may be a significant step in that direction in some cases.
Humoral immune response of Japanese eel, Anguilla japonica Temminck & Schlegel, to Pleistophora anguillarum Hoshina, 1951 (Microspora)
Authors: Hung H‐W , Lo C‐F , Tseng C‐C , Kou G‐H
Published: April 2006

A humoral response of Japanese eel, Anguilla japonica Temminck & Schlegel, to the microsporean Pleistophora anguillarum Hoshina was demonstrated using immunoblotting and an enzyme‐linked immunosorbent assay (ELISA). Japanese eel immunoglobulin was purified by affinity chromatography. The immunoglobulin was composed of 25‐kDa light chains and 72‐kDa heavy chains. The ELISA values of P. anguillarum antibodies in naturally infected fish sera were significantly higher than those of clinically healthy fish. Spore proteins from the microsporean were separated by electrophoresis and subjected to analysis by Western blot. Sera from naturally infected fish showed different reaction patterns to the spore proteins. While the sera randomly selected from naturally infected eels all showed a significant positive reaction to P. anguillarum antigens, the mucus from only three out of the nine infected eels reacted positively in the ELISA test. Subsequent analyses indicated that there was no significant difference in the amount of mucus immunoglobulin among the tested eels. Therefore, the generally lower ELISA values of mucosal anti‐P. anguillarum antibodies from the infected eels tested were evidently not caused by a lack of immunoglobulin per se, but seem to be the result of a lack of anti‐P. anguillarum antibodies in the mucus and/or a lower affinity in the anti‐P. anguillarum antibodies that were present.
Digenean (Bucephalidae) infections in commercial scallops, Pecten fumatus Reeve, and doughboy scallops, Chlamys (Mimachlamys) asperrima (Lamarck), in Jervis Bay, New South Wales
Authors: Heasman M P , O'Connor W A , Frazer A W J
Published: April 2006

Sympatric populations of the hermaphroditic scallop, Pecten fumatus Reeve, and of the dioecious scallop, Chlamys (Mimachlamys) asperrima (Lamarck), from Jervis Bay, New South Wales, Australia, were sampled between October 1991 and December 1994. Over the first 2 years, 5.1% of adult P. fumatus and 4.5% of adult C. asperrima were infected with a trematode, Bucephalus sp., that causes parasitic castration. A significant increase in the numbers of infected scallops occurred in spring 1993, teaching 63% in P. fumatus and 24% in C asperrima in May and March 1994, respectively. The prevalence of infection increased with scallop size, reaching 66% in P. fumatus greater than 80 mm in shell height and 40% in C. asperrima greater than 75 mm in 1994. Seasonal and interannual variations in parasitism for the P. fumatus recorded over a continuous period of 5 years in Jervis Bay are discussed, as are interspecies differences and the potential impact of the parasitic castration on reproductive potential and marketability of P. fumatus and C. asperrima.
Experimental infection of Atlantic halibut, Hippoglossus hippoglossus L., yolk‐sac larvae with infectious pancreatic necrosis virus: detection of virus by immunohistochemistry and in situ hybridization*
Authors: Biering E , Bergh Ø
Published: April 2006

Three different concentrations (107, 105 and 103 TCID50 ml−1) of infectious pancreatic necrosis virus (IPNV) serotype Sp isolated from Atlantic halibut, Hippoglossus hippoglossus L., were used to bath‐challenge Atlantic halibut yolk‐sac larvae. The larvae challenged with 107 TCID50 ml−1 suffered significantly higher cumulative mortality than the other challenged groups and the control group, and affected individuals displayed necrosis of the intestine, liver and kidney. In larvae from the groups challenged with 107 and 105 TCID50 ml−1, IPNV was detected by immunohistochemistry and in situ RNA/DNA hybridization in the intestine, liver and kidney. In addition, some individuals stained IPNV‐positive in the heart and eye/ brain region. Detection by in situ hybridization did not appear to be more sensitive than immunohistochemistry. However, background staining was virtually absent in comparison with immunohistochemistry, and the staining seemed to be more distinctly localized to the cytoplasm of infected cells. The results show that farmed halibut yolk‐sac larvae can be infected by IPNV immediately after hatching, with resulting high mortality. As the larvae are not immunologically mature at this stage of development, vaccination is not recommended.
Recombinant channel catfish virus (Ictalurid herpesvirus 1) can express foreign genes and induce antibody production against the gene product
Authors: Zhang H G , Hanson L A
Published: April 2006

The potential use of channel catfish virus (CCV) (Ictalurid herpesvirus 1) as a vaccine vector for the channel catfish industry was investigated by inserting the Escherichia coli lacZ gene into the CCV genome and evaluating the immune response to the foreign gene product in catfish exposed to the recombinant. The recombinant virus was produced by inserting the lacZ in reading frame with the ATG start codon of the CCV thymidine kinase (TK) gene in the recombinant transfer plasmid pBSCV457 described previously. The plasmid was then cotransfected with CCV DNA in a TK gene‐mediated selectable homologous recombination. The recombinant progeny were selected by resistance to 0.1 mM acycloguanosine (acyclovir) and the production of blue plaques in the presence of 5‐bromo‐4‐chloro‐3‐indolyl‐β‐D‐galactopyranoside (X‐gal). The resultant construct (CCVlacZ) was TK−, and contained the lacZ gene at both TK loci in the genome. β‐Galactosidase expression in infected CCO ceils reached 0.53 μg per 106 CCO cells at 12 h post‐infection. When channel catfish fingerlings were immersion exposed to CCVlacZ, these developed an antibody response to the inserted foreign gene product which peaked at approximately 15–20 days post‐infection. Additionally, the anti‐β‐galactosidase response was significantly enhanced when the fingerlings were re‐exposed to the virus 20 days after the initial exposure. These results demonstrate that foreign genes can be inserted into and expressed by CCV and that such constructs could be used as vaccine vectors.
Accumulation of immunomodulatory laminaran (β(1,3)‐D‐glucan) in the heart, spleen and kidney of Atlantic cod, Gadus morhua L.
Authors: Dalmo R A , Ingebrigtsen K , Sveinbjørnsson B , Seljelid R
Published: April 2006

The tissue distribution of 3H‐ and FITC‐lammaran in Atlantic cod, Gadus morhua L., was investigated after intravenous administration. Liquid scintillation counting and whole‐body autoradiography revealed a substantial accumulation of 3H‐labelled laminaran in the heart throughout the experimental period (1 h to 12 days). High amounts of the immunomodulator were also present in the spleen, anterior kidney and posterior kidney during the study. Renal excretion and intestinal exsorption were the main elimination pathways. Fluorescence microscopic examination revealed accumulation of FITC‐labelled laminaran in macrophages in the kidney and ellipsoid sheath cells (macrophages and reticular cells) in the spleen. Furthermore, endothelial entrapment in the heart was pronounced. Endothelial cells in the kidney also contained the FITC‐labelled immunomodulator. Immunohistochemical analysis, using anti‐β(l,3)‐D‐glucopyranose antibody, also showed endothelial uptake of laminaran in the heart. The present investigation shows that laminaran accumulates and is retained in immunologically relevant cells in the Atlantic cod.
Production of monoclonal antibodies against yellowtail ascites virus
Authors: Nakajima K , Sorimachi M
Published: April 2006

A total of 31 antibody‐secreting hybridoma cells against the yellowtail ascites virus (YAV) were established. These monoclonal antibodies (MAbs) reacted with the cytoplasm of YAV‐infected CHSE‐214 cells, but not with uninfected CHSE‐214 cells in an immunofluorescence test. Using these MAbs, two classes of polypeptides (VP2 and VP3) were characterized by immunoprecipitation followed by SDS‐PAGE, although one MAb did not react with either polypeptide. Fifteen out of the 17 MAbs that were reactive with VP2 polypeptides neutralized virus infectivity, but all 13 MAbs that were reactive with VP3 did not neutralize infectivity. In the immunofluorescence test, 29 out of the 31 MAbs obtained showed the same reaction pattern to 12 YAV isolates from yellowtail, Seriola quinqueradiata, goldstriped amberjack, Seriola aureovittata, and threeline grunt, Parapristipoma trilineatum, from different geographical regions. The remaining two MAbs showed slightly different reaction patterns to the YAV isolates. The reaction patterns of the MAbs to the VR‐299, Sp and Ab strains of IPNV were also investigated. Fourteen MAbs reacted to all three IPNV strains. The other 17 MAbs showed a negative reaction with at least one strain.
Experimental infection of Atlantic halibut, Hippoglossus hippoglossus L., yolk‐sac larvae with infectious pancreatic necrosis virus: detection of virus by immunohistochemistry and in situ hybridization
Authors: Biering E , Bergh Ø
Published: April 2006

Three different concentrations (107, 105 and 103 TCID50 ml‐1) of infectious pancreatic necrosis virus (IPNV) serotype Sp isolated from Atlantic halibut, Hippoglossus hippoglossus L., were used to bath‐challenge Atlantic halibut yolk‐sac larvae. The larvae challenged with 107 TCID50 ml‐1 suffered significantly higher cumulative mortality than the other challenged groups and the control group, and affected individuals displayed necrosis of the intestine, liver and kidney. In larvae from the groups challenged with 107 and 105 TCID50 ml‐1, IPNV was detected by immunohistochemistry and in situ RNA/DNA hybridization in the intestine, liver and kidney. In addition, some individuals stained IPNV‐positive in the heart and eye/brain region. Detection by in situ hybridization did not appear to be more sensitive than immunohistochemistry. However, background staining was virtually absent in comparison with immunohistochemistry, and the staining seemed to be more distinctly localized to the cytoplasm of infected cells. The results show that farmed halibut yolk‐sac larvae can be infected by IPNV immediately after hatching, with resulting high mortality. As the larvae are not immunologically mature at this stage of development, vaccination is not recommended.
Prostaglandin E2 Receptors in the Chicken Spinal Cord:
Authors: Pralong E. , Vesin M.‐F. , Droz B.
Published: April 2006

High and low affinity binding sites for PGE2 were localized at the cellular level by means of radioautography. Two types of radioautographic reactions were observed in cryostat sections incubated with 0.6 nM [3H]PGE2: (i) a diffuse reaction scattered over the neuropil; (ii) a stronger reaction over the perikarya of some motoneurons. However, not all the motoneurons were equally labelled; the density of silver grains increased 12 times from poorly labelled to highly labelled cells. After incubation with an excess of unlabelled PGE2 the labelling was drastically reduced over motoneurons and the neuropil, so that the specific binding corresponded to 90 and 85% respectively of the total binding. Two facts indicated that the motoneurons possessed mainly high affinity binding sites which could be saturated by PGE2 concentrations in the nanomolar range: (i) a five‐fold increase of [3H]PGE2 concentration (from 0.6 to 3 nM) produced only a 1.5 times increase in the density of silver grains over the perikarya; (ii) incubation in presence of 14 nM unlabelled PGE2 induced a drastic reduction of 0.6 nM [3H]PGE2 binding to the motoneurons. The presence of high affinity binding sites in motoneurons suggests that PGE2 could act as a modulator of spinal reflexes.
Spatial Organization of the Maculo‐Ocular Reflex of the Rat: Responses During Off‐Vertical Axis Rotation
Authors: Hess B. J. M. , Dieringer N.
Published: April 2006

Pigmented, head restrained rats were rotated on a turntable about a tilted axis (off‐vertical axis rotation; OVAR) in darkness. Evoked eye movements in the horizontal, vertical and torsional planes were recorded simultaneously with a dual search coil in a magnetic field, horizontal response components of both eyes were recorded with a coil on either eye. OVAR resulted in a persisting horizontal, unidirectional ocular nystagmus, compensatory in direction for the rotation of head in space. Superimposed upon this nystagmus were slower cyclic responses of the eye in the vertical and torsional movement planes, that were tightly phase locked with changing head positions in space: ocular depression/elevation with right ear up/down and ocular intorsion/extorsion with nose up/down. Simultaneous recordings of horizontal response components from both eyes revealed phase and gain differences between the horizontal movement components of both eyes, that resulted in a cyclic modulation of the vergence angle. Convergence of the lines of sight during nose up and divergence during nose down, adequate compensatory responses in light for changes in the viewing distance, were actually observed in darkness. Thus the utricular maculo‐ocular reflex takes part of the visual consequences of a translational gaze shift into account. It reduces expected retinal disparities by appropriate and rapid vertical, torsional and vergence response components in the same way as canal‐ocular reflexes ‘compensate’ for direction and velocity of expected retinal image slip during head rotation.
Phorbol Ester Interferes with [3H]Norepinephrine Accumulation into Monolayers of PC 12 Cells by Stimulating the Release of Endogenous Norepinephrine
Authors: Tas Piet W. L. , Schömig Edgar , Koschel Klaus
Published: April 2006

In this study we have observed an inhibition of the [3H]norepinephrine ([3H]NE) accumulation into rat phaeochromocytoma PC 12 cells by phorbol 12‐myristate 13‐acetate (PMA), whereas a biologically inactive phorbol ester was without effect. The inhibition was no longer observed when the PC 12 cells were preincubated with 10 μM reserpine, which inhibits the uptake of norepinephrine into the storage vesicles. This suggested a role of the intact vesicles in the inhibitory phenomenon. Subsequently we could show that PMA increased the efflux of [3H]NE from PC 12 cells in a dose dependent manner. It seemed likely, therefore, that the increased release of endogenous norepinephrine from PC 12 cells by the phorbol ester competed with exogenous [3H]NE for uptake by the plasma membrane NE (uptake1) carrier into the cells. Two observations were in agreement with such a model: (i) an increase in the external NE concentration decreased the effect of PMA on the [3H]NE uptake; and (ii) desensitization of the protein kinase C by long term treatment of the PC 12 cells with phorbol ester abolished the PMA effect on both [3H]NE efflux and [3H]NE uptake.
Quantification and Comparison of Cell Properties in Cat's Striate Cortex Determined by Different Types of Stimuli
Authors: Wörgötter Florentin , Gründel O. , Eysel U. Th.
Published: April 2006

Direction and orientation tuning elicited by moving bars, flashing bars and a moving noise field were compared in cells in area 17 of the cat. Fourier analysis of tuning curves (SDO‐analysis) was applied to quantify the general sensitivity (S) to visual stimulation, tuning strength to direction(D) and orientation (O), as well as the preferred direction (PD) and orientation (PO). Results from SDO‐analysis were compared with the commonly used direction index and half‐width‐at‐half‐height orientational tuning parameter and it is demonstrated that the commonly used parameters can be replaced and are superseded by the results from SDO‐analysis. The comparison of the responses elicited by the different types of stimuli showed that a linear correlation between D (or O) components was mainly found in simple cells, while in most cases no correlation was obtained for complex cells. Since several of the simple cells also showed no linear relationship, a direct mutual prediction of the S, D and O components can only be achieved for ∼50% of the cortical cells applying commonly used stimulus types. The general responsiveness (S) shows that flashing bar stimuli are at least as effective as moving bars, whereas moving noise stimulates cortical cells more weakly. A moving bar tends to increase the orientation tuning (O) in most cells and with a moving noise stimulus predominantly the directional tuning (D) of complex cells is strongly enhanced. In conclusion, Fourier analysis of tuning curves (SDO‐analysis) provides a valuable and simple tool for the quantification of direction and orientation specificity. Motion enhances the cortical response specificity which indicates the involvement of facilitation or inhibition exclusively induced by movement.