摘要:

Abstract.The predominant cell surface protein (A‐protein) ofAeromonas salmonicidahas been purified by a method utilizing a glycine/hydrochloridc extraction from whole cells and HPLC/ion exchanger (DEAE) columns. This procedure yielded two LPS‐frec molecules (a 40‐ and a 50‐kDa form) both shown to contain A‐protein determinants. The former appears to be a digest product of the latter, as a serine protease produced byA. salmonicidawas shown to process the 50‐kDa form into a 40‐kDa moleculein vitro.The A‐layer protein was shown to contain one isoform, although multiple isoelectric forms appeared as preparative artifacts, probably due to deamidation. The A‐layer protein and LPS arc the most significant surface antigens recognized by the Atlantic salmon B‐lymphocytes or antibodies. Immunological studies of LPS‐free and LPS‐containing A‐protein preparations were undertaken to test whether the two components behave like antigenie competitors or whether the LPS moiety could adjuvant the antibody response against the A‐protein. The latt

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00645.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Ultrastructural changes occurring in juvenile channel catfish,Ictalurus punctatusRatinesque, hepatocytes were examined following exposure to carbon tetrachloride (CCl4). Juvenile catfish were intraperitoneally injected with a sublethal dose of undiluted CCl4and controls, used for comparisons, received physiological saline. The rough endoplasmic rcticulum (RER) was slightly dilated by 1 h and was significantly dilated by 4 and 24 h post‐CCl4‐exposure. At 4 h, the RER became degranulated, mitochondrial eristae indistinct with electron dense flocculant matrieal deposits, and nuclear membranes indented. Autophagic vacuoles were present in some hepatocytes. Within 48 h post‐exposure, the hepatocytes were indistinguishable from control hepatocytes. CCl4can induce reversible or irreversible cell damage which appears dose depe

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00646.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Cultures ofAeromonas salmonicida, subspeciessalmonicidaandachromogenes, produced considerable quantities of inhibitors that affected extracellular bacterial proteases (endopeplidases), as well as some animal trypsins (from pig, salmon and trout) included in this study. Electrophoretic separation of these inhibitors revealed a complex of three to four single factors which were similar for the two subspecies. One of the factors only inhibited protease from the homologus subspecies, while another only affected enzyme from the other subspecies (cross‐wise inhibition). Both subspecies produced a factor which inhibited animal trypsins only. Subspeciessalmonicidaalso possessed a factor which inhibited most of the examined proteases unspecifically. In young cultures (2–3 days at 15°C), the inhibitors were demonstrable both in the disintegrated cell material and in cell‐free culture filtrate. The activity of the factor which only inhibited the protease from subspeciessalmonicidacould be increased considerably by moderate heating of the material. The effect of inhibitors produced by other relevant Gram‐negative bacteria on the proteases of theA. salmonicidasubspecies included was more limited. Considerable quantities of inhibitors against proteases of the subspeciessalmonicidaandachromogeneswere demonstrated in cell‐free filtrates of two commercially available vaccines against furunculos

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00647.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Exposure of surgically damaged skin of Atlantic salmon,Salmo salarL., to low levels of ultraviolet‐B radiation in clear water showed that the basic mechanism of superficial wound healing, characterized by epidermal migration, was unaffected. However, the migrating cells were more vulnerable to the necrotizing effects of the irradiation than the surrounding donor epithelium and longer standing effects such as wound contracturc and resolution of epidermal structure failed to occu

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00648.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.A method ofin situhybridization with biotinylated probes is described for the spceific detection of theHerpesvirus cyprini(CHV) genome, both in CHV infected cell cultures and tissue specimens prepared from carp fry infected with the same virus. From molecularly cloned PstI‐fragments of CHV DNA, two fragments were selected as probes forin situhybridization which had no detectable homology, either with DNA of fathead minnow (FHM) cells used for virus propagation, or with the DNA of several fish herpes‐viruses. The method ofin situhybridization was based on a system using streptavidin‐biotinylated alkaline phosphatase for the detection of hybridiz

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00649.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Salmonid fish at fish farms in northern and central Finland and perch,Perca fluviatilisL., roach,Rutilus rutilus(L.), and whitefish,Coregonussp., from four lakes in central Finland were studied between 1985 and 1990 for the occurrence ofYersinia ruckeri.The bacteria were found in fish from both areas, but in most cases, only single diseased salmon,Salmo salarL., brown trout, S.truttaL., rainbow trout,Oncorhynchus mykiss(Walbaum), whitefish and perch were encountered and were always connected with stress conditions. One clinical outbreak occured in salmon fingerlings in northern Finland, and the fish were successfully treated with trimethoprim‐sulpha. Monthly monitoring of lake fish revealed two symptomless carrier perch in two lakes. Outwith the main study a moribund perch with yersiniosis was found in a polluted lake, and for the first time in Finland, a rainbow trout was also found to have contracted yersiniosis in a small private pond. Sorbitol‐positive and negative isolates have been found to occur in both moribund and carrier farmed fish, indicating that the sorbitol test is not essential when evaluating the pathogenicity ofY. ruck

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00650.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Broad, non‐septate, fungal hyphae are a constant finding in the necrotising dermatitis lesions and dermal ulcers characteristic of red spot disease. During a one‐year period, fungi with hyphae morphologically consistent with those seen in histological sections of lesions were recovered from 27 out of 28 lesions on sea mullet,Mugil cephalusL., yellowfin bream,Acanthopagrus australis(Owen), and sand whiting,Sillago ciliataCuvier, collected from three widely separated river systems in eastern Australia. Cultural and morphological characteristics, including spore formation, of 24 of these isolates were examined. In addition, tolerances to different salinities, growth on different media and growth at different temperatures were studied for three representative isolates, one from each species of fish. These studies suggest that all isolates belonged to a single species within the genusAphanomyces.Their role in the pathogenesis of red spot disease, and their relationship with otherAphanomycesspp. affecting fish, is discus

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00651.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Twenty‐eight strains of A. Hydeophila, 18 from fish with epizootic ulcerative syndrome (EUS) and 10 from apparently normal fish, were examined for their ability to produce cylotoxins and haemolysins. Bacterial culture supernantants were tested for cytotoxin elaborated using the visual cell damage technique and a novel clorimetric method. Two types of target cells were used and the WEHI cells were reproducibly more sensitive than Vero cells in both the cytotoxin assays. Cytotoxin‐producer strains were more frequently associated with EUS‐infected fish compared to normal fish. Haemolysin‐producing strains were equally present in healthy and EUS‐positive fish, and the haemolysin was not correlated with cytotoxin production. It appears that the progression of pathogenicity of EUS may be linked with the presence of cytotoxic strains of A. hydrophila in the EU

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00652.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Thirty‐four A. hydrophila strains isolated from various fish species and several geographical locations in Malaysia were examined for their antibiotic resistance pattern and plasmid carriage. All strains were found to possess multiple resisitance, most commonly to ampicillin and carbenicillin. Six different antibiogroups representing 18 different antibiotic patterns were obtained. There were no differences in the resistance patterns of A. hydrophila isolates from healthy and diseased fish with ulcerative syndrome. Rifampicin was found to be the most active antibiotic against these strains. Isolation of plasmid DNA have a plasmid occurrence rate of only 14·7%. The molecular sizes of these plasmids ranged from 2·6 to 6Mda. Multiple carriage of plasmid is more likely with strains having three of four plasm

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00653.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Anecdotal reports from the Scottish fish farming industry suggested a reduction in the sensitivity of salmon lice,Lepeophtheirus salmonis, to the organophosphate dichlorvos. In this study, pro‐adult and adult lice were collected from marine salmon sites showing a variety of ‘sensitivities’ to dichlorvos and subjected to dichlorvos exposure at a range of doses for a 48‐h periodin vitro.From the lice mortalities, 24 and 48 h LC50 values were calculated, and using a ‘sensitive’ source of lice as a reference, resistance ratios calculated. The data generated suggests thatL. salmonisfrom different geographic areas shows differences in sensitivity to dichlorvos. The implications for the salmon farming industry ar

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00654.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY