Aeromonas salmonicida: Relationship between Extracellular Growth Products and Isolate Virulence

1981 ◽  
Vol 38 (11) ◽  
pp. 1322-1326 ◽  
Author(s):  
Rocco C. Cipriano ◽  
Billy R. Griffin ◽  
Burton C. Lidgerding

Extracellular growth products, extracted from culture supernatants of Aeromonas salmonicida by precipitation with ammonium sulfate and ethanol, were resolved into four fractions by ion-exchange chromatography. Although one of these (fraction II) possessed leukocytolytic activity, virulence of the pathogen was not associated with leukocytotoxicity. A positive correlation was established, however, between virulence and the toxicity of extracted material to cultured rainbow trout gonad (RTG-2) cells. The crude material and fractions II and III from virulent isolates were more toxic to RTG-2 cells than were similar preparations from avirulent isolates. Preparations from virulent isolates caused hemorrhaging, lesion development, and mortality when injected intramuscularly into brook trout (Salvelinus fontinalis) and Atlantic salmon (Salmo solar). Rainbow trout (Salmo gairdneri) were more resistant and lesions could be produced only with fraction II. Fraction II also possessed proteolytic activity.Key words: Aeromonas salmonicida, furunculosis, pathogenicity, salmonids, extracellular products, cytotoxicity, leukocytolysis, proteolysis, fishes

1985 ◽  
Vol 42 (7) ◽  
pp. 1290-1295 ◽  
Author(s):  
Rocco C. Cipriano ◽  
Stephen W. Pyle

Adjuvant-dependent immunity resulted in agglutinin activity against Aeromonas salmonicida in sera of convalescent fishes. Rainbow trout (Salmo gairdneri), brown trout (Salmo salar), and brook trout (Salvelinus fontinalis) that had recovered from natural furunculosis produced serum agglutinin antibodies predominately against a specific chromatographic fraction (EcF1) of the bacterium's extracellular product. EcF1 was resolved by ion-exchange chromatography from DEAE SephadexA-25. When EcF1 was emulsified in Freund's incomplete adjuvant and injected intraperitoneally, brook trout were protected against experimental challenge; brook trout vaccinated with EcF1 only were not protected against furunculosis. EcF1, examined by immunodiffusion tests, SDS – polyacrylamide gel electrophoresis, and Western blot immunoassays, shared certain properties with bacterial endotoxin. EcF1 and endotoxin preparations both contained immunoreactive lipopolysaccharides which indicated that adjuvant-dependent immunity to A. salmonicida is related to endotoxin.


1982 ◽  
Vol 39 (1) ◽  
pp. 218-221 ◽  
Author(s):  
Rocco C. Cipriano

Brook trout (Salvelinus fontinalis) passively immunized with antisera from rainbow trout (Salmo gairdneri) prepared against virulent or avirulent cultures of Aeromonas salmonicida were equally protected from challenges with concentrated suspensions (109 cells/mL) of A. salmonicida. Brook trout immunized with washed or unwashed formalin-killed virulent cells of A. salmonicida had mean humoral agglutinating antibody titers of 14 (washed cells) and 205 (unwashed cells) after 21 d. However, fish so immunized were not protected when exposed to a virulent challenge. Trout inoculated with crude extracellular material extracted from culture supernatants had a mean agglutinin titer of 122, and fish so immunized were resistant to challenge. Keywords: Aeromonas salmonicida, Salvelinus fontinalis, Salmo gairdneri, immunization, antigens, extracellular material, protection, challenge, fishes


1972 ◽  
Vol 29 (11) ◽  
pp. 1615-1624 ◽  
Author(s):  
James E. Bryan ◽  
P. A. Larkin

Analyses of stomach contents showed that the kinds of prey eaten by brook trout (Salvelinus fontinalis), cutthroat trout (Salmo clarki), and rainbow trout (Salmo gairdneri) were seldom distributed at random among the individuals. Repeated observation of food eaten by individuals in a stream and ponds showed that prey types were eaten in proportions which were characteristic for an individual.Specialization occurred on several different kinds of prey. Although the degree of specialization was higher during shorter intervals, the data suggested that some specialization persisted for half a year. There were no striking correlations between degree of specialization and other individual properties such as size, growth rate, weight of food, number of food items, previous specialization, or area of recapture.In addition to the observations on trout in relatively undisturbed habitats, a field experiment was conducted using laboratory-reared rainbow trout held in small ponds. The food of each trout in the experiment was sampled repeatedly. In analysis of variance, interaction among the individuals and kinds of prey eaten showed that food specialization occurred. Both the absolute and relative abundance of potential prey were constant during the experiment.


1980 ◽  
Vol 37 (9) ◽  
pp. 1421-1425 ◽  
Author(s):  
Larry J. Paulson

Ammonia excretion by brook trout (Salvelinus fontinalis) and rainbow trout (Salmo gairdneri) was measured in relation to nitrogen consumption, body weight (15–154 g for rainbow trout and 50–360 g for brook trout), and temperature (11.2–21.0 °C) under laboratory conditions. Four natural diets, collected from Castle Lake, California, and a commercial pellet diet were fed to the trout in gelatin capsules at feeding rates from 2.5 to 5% body weight∙d−1. Nitrogen consumption was the most important factor influencing ammonia excretion, followed by body weight and temperature. Testing the models with an independent data set revealed good agreement between measured and predicted rates of excretion. The models seem to estimate adequately ammonia excretion by trout in both natural and artificial aquatic systems.Key words: models, ammonia excretion, nitrogen consumption, body weight, temperature, multiple regression, rainbow trout, brook trout


1982 ◽  
Vol 39 (6) ◽  
pp. 926-928 ◽  
Author(s):  
Ken Wolf ◽  
Maria E. Markiw

We processed 2-yr-old rainbow trout (Salmo gairdneri) and brook trout (Salvelinus fontinalis) with clinical whirling disease, which is caused by Myxosoma cerebralis, in one of the following ways: iced, iced and brined, or iced, brined, and hot smoked at 66 °C for 40 min. Skeletal elements of each group were added to tanks containing soil samples from an aquatic environment free of M. cerebralis and aged for 4 mo at 12.5 °C. Following this we assayed for infectivity by holding susceptible rainbow trout fry for 3 mo in the tanks of aquatic soil and skeletal elements. The fry were then examined for M. cerebralis spores. Spores were found in the fry from tanks that had received iced and iced and brined samples, but not in fry from the tanks containing hot smoked tissue, healthy tissue, or no tissue — the last two being negative controls.Key words: whirling disease, Myxosoma cerebralis, heat inactivation, hot smoking


1982 ◽  
Vol 39 (1) ◽  
pp. 225-228 ◽  
Author(s):  
Robert N. Swanson ◽  
James H. Gillespie

Experimental infection with infectious pancreatic necrosis virus (IPNV) was achieved in yearling rainbow trout (Salmo gairdneri) and 7-mo-old brook trout (Salvelinus fontinalis) by intraperitoneal inoculation and by water contact, respectively. Blood removed periodically from both groups of fish was fractionated and various blood components examined for virus. IPNV was recovered consistently from the plasma and mononuclear-enriched blood fractions of the rainbow trout from 1 to 19 d postinoculation (DPI) and also was detected in the mononuclear fraction on 33 DPI. In the brook trout virus was recovered from 3 to 40 DPI in the plasma and from 7 to 40 DPI in the mononuclear fraction. Thus a viremia appeared to be important in the early stages of experimental IPNV infection and infectious virus was found both free in the plasma and in association with an undetermined cell population present in the mononuclear component of blood.Key words: infectious pancreatic necrosis, blood, fish disease, Salmo gairdneri, Salvelinus fontinalis


1982 ◽  
Vol 39 (11) ◽  
pp. 1512-1518 ◽  
Author(s):  
Rocco C. Cipriano

Growth products from virulent (3.93 and 3.101), an avirulent (3.10), and an atypical strain (3.111) of Aeromonas salmonicida yielded four protein containing fractions (designated fractions 1, 2, 3, 4) following chromatography on DEAE Sephadex A-25 of crude material that was precipitated from broth culture supernatants with (NH4)2SO4 and ethanol. Vaccination trials, in which each of the four fractions from a virulent and an avirulent strain were injected intraperitoneally at a dose of 5 μg protein into brook trout (Salvelinus fontinalis) indicated that only fraction 4 consistently protected trout from experimental challenges. Immunizing fish with fraction 4 that was emulsified in Freund's incomplete adjuvant also protected trout from challenge but did not enhance protection. Additional brook trout that were immunized by injection with fraction 4 derived from either of two virulent, an avirulent, or an atypical strain of A. salmonicida were also protected from contact challenge with a different challenge strain. Fraction 4 was partially characterized as a glycoprotein; the protein subunit fraction had an approximate molecular weight of 66 000 daltons. Rabbit antiserum prepared against fraction 4 reacted on agar gel diffusion plates to form a single precipitin band with the homologous fraction 4 antigen but this antiserum did not cross react with either purified preparations of bacterial endotoxin or A-layer protein.Key words: Aeromonas salmonicida, Salvelinus fontinalis, growth products, fraction 4, glycoprotein, virulent, avirulent, atypical strains, contact experimental challenge


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