摘要:

Abstract.Intravascular injection of purified 70‐kDa protease or GCAT‐LPS fromAeromonas salmonicida, or both, invariably led to consumptive coagulopathy within 2h in Atlantic salmon,Salmo salarL. By entering the coagulation cascade at two different levels, the two enzymes work in concert in thrombus formation, the significance being that circulatory failure is probably the major cause of death in acute furunculosis. Only intravascular injection of GCAT‐LPS led to consumptive coagulopathy in rainbow trout,Oncorhynchus mykiss(Walbaum), despite the fact that trout received only half the GCAT dose, and/or four times the protease activity administered to salmon. These results indicate that salmon is, by far, the most susceptible to protease and suggest that rainbow trout is the most susceptible to GCAT‐LPS. The substrate profile of the purified protease gave supporting evidence that it works as activated coagulation factor X. The protease is inhibitedin vitroby antithrombin and by α2‐macroglobulin and both inhibitors are consumedin vivoin response to intravascular administration of the enzymes, thus showing a potential for AT and α2M to inhibit the protease alsoin vivo.Provided such plasma antiprotease activities are correlated with resistance to the disease, and the inhibitors show genetic variation they would be promising candidates for indirect selection and hence a means to prevent furunculosis independently of vaccines. Circulating inhibitors of GCAT‐LPS remain to

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00658.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Western blot (WB) and electroimmunotransfer blot (EITB) methods were used to monitor bacterial soluble antigens and scroconversion profiles, respectively, in Atlantic salmon,Salmo salarL., experimentally challenged withRenibacterium salmoninarum.The two challenged populations exhibited differences in susceptibility toR. salmoninarumpermitting an evaluation of the methods in fish populations harbouring different levels of the pathogen, WB detection ofR. salmoninarumsoluble antigens in serum provided a sensitive method for detecting pathogen presence during the active infection stages. For comparison, results for drop‐plate culture and direct fluorescent antibody techniques were obtained. During the recovery phase, surviving fish were negative for the pathogen by these methods. However,>90% of challenged fish sampled from early infection stages to the end of the experimental period (141 days post‐infection) were scropositive by the EITB assay for Atlantic salmon immunoglobulin reactive withR. salmoninarumsoluble antigens. The results suggest that these methods for detectingR. salmoninarumor its soluble antigens may be useful during active infections. However, asymptomatic fish populations exposed to the pathogen, perhaps having recovered from an active infection and representing potential disease carrier sources, may be more readily identified by antigen‐specific antibodies using methods such as the EITB

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00659.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.The development of a selective‐differential medium (ROD) for the isolation ofYersinia ruckerifrom carrier and clinically infected rainbow trout,Oncorhynchus mykiss(Walbaum), is described. This medium was a useful aid for the detection ofY. ruckeriin faecal material and allowed the epidemiology of enteric redmouth disease to be studied in greater detail. Regular use of ROD at two fish farms in southern England has demonstrated that isolation ofY. ruckerifrom faeces was possible under field conditions up to 4–6 weeks before acute clinical kidney infection occur

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00660.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00661.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.The optimum temperature forin vitromultiplication ofCryptobia salmositicawas 10°C. The avirulent strain multiplied more rapidly than the virulent strain. The haemolytic components, lytic component (LC) and immune complex‐forming component (ICC), were secreted by the two strains into the culture medium and were detectable from one week post‐inoculation. The haemolytic activity in the supernatant increased with increasing parasite numbers in both strains. Although cultures of the avirulent strain had higher parasite numbers than those of the virulent strain, the haemolytic activity was significantly lower than that of the virulent strain. Antiserum against ICC was produced in rabbit by immunization with ICC‐coated rainbow trout red blood

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00662.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00663.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00664.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00665.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY