摘要:

Abstract.Infectious pancreatic necrosis virus (IPNV) contains two segments of double‐ stranded RNA (the larger RNA segment, A; and a smaller RNA segment, B). The IPNV‐ Buhl isolate belongs to the VR299 serotype, and eel virus European (EVE) is serologically the same as the Ab serotype. IPNV‐Buhl is virulent to rainbow trout fry,Oncorhynchus mykiss(Walbaum), whereas EVE is avirulent. To determine the genetic basis for the difference of the virulence, intertypic reassortants were made between IPNV‐Buhl and EVE. The reassortants with the genotypes of P/E (segment A of IPNV‐Buhl and segment B of EVE) and E/P (segment A of EVE and segment B of IPNV‐Buhl) were studied for their pathogenicity to rainbow trout fry. The P/E reassortant was highly virulent, similar to the IPNV‐Buhl parent (P/P), while the E/P reassortant was avirulent, as was the EVE parent (E/E). A high level of viral replication was observed in almost all organs of the fry infected with the P/E reassortant and the IPNV‐Buhl parent. In contrast, viral replication was restricted to the epidermal cells of the fry infected with the E/P reassortant and the EVE parent. The results demonstrate that the larger RNA segment (RNA segment A) of IPNV is related to cell tropismin vivoand is responsible for virulence in ra

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00666.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Intraperitoncal injection of β‐l,3 glucan in channel catfish,Ictalurus punctatusRafinesque, greatly reduces mortality from experimental infection withEdwardsiella ictaluri.Anterior kidney phagocytes from fish receiving glucan had enhanced phagocytic and bactericidal ability. The elevated bactericidal ability of phagocytes was not accompanied by increased production of hydrogen peroxide. Fish injected with glucan responded to subsequentE. ictaluriimmunizations with higher serum antibody titres relative to the control catfish. The timing of glucan administration and antigen immunization was also important. These results indicate that β‐1,3 glucan potentially could be utilized prophylactically as an immunomodulator in channel ca

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00667.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Electrophoretic analysis of six types of tissue (serum, erythrocyte, liver, kidney, muscle and eye) and seven different isoenzymes (LDH, MDH, Est, ADH, IDH, α‐GPDH and SOD) from both healthy grass carp,Ctenopharyngodon idellusCuvier&Valenciennes, and carp affected by haemorrhagic disease was performed. It was found that: (1) Enzymes from diseased grass carp showed the most drastic changes within each tissue. The absolute activity of LDH in serum from the diseased fish increased to approximately twice that of the healthy fish; whereas the relative activity of A4and A3B1, the main components of A sub‐base in both serum and erythrocytes, was accelerated. (2) The isoenzymic changes in the control groups, diseased fish, artificially infected fish and healthy fish from diseased ponds indicated that biochemical changes occurred in the tissues before pathological ch

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00668.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.The possibility of oral transmission of the pleistophorid microsporidian parasiteVavraia parastacidaLangdon from marron,Cherax tenuimanus(Smith), was investigated by feeding infected marron and yabby,Cherax albidusClark, muscle to juvenile marron and yabbies. Infections were established in a proportion of marron and yabbies with tissue from both crayfish, and both mounted a vigorous haemocytic response which failed to arrest progress of the disease. The disease appeared to progress more rapidly in the yabbies, in which no natural cases have been found. It would appear inadvisable to mix marron and yabbies on crayfish farms unless the marron are first demonstrated to be free of the parasite. As an intermediate host is not essential to transmission, which can occur through cannibalism, the exclusion of possible vectors will not control vavraiasis on crayfish farms, It remains possible that an alternate life cycle involving intermediate or transport hosts also takes place.

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00669.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Atlantic salmon,Salmo salarL., parr were injected intraperitoneally with different quantities of formalin (37% formaldehyde) following anaesthetization with either benzocaine (ethyl‐p‐aminobenzoate) or chlorbutol (1,1,1,‐trichloro 2‐methyl‐2‐propanol) The LD50for injected formaldehyde was found to be approximately 50mg kg−1body weight. The type and concentration of the anaesthetic used did not influence mortality rates. Formalin is commonly used to inactivate microorganisms in vaccines. Doses of formalin which were shown to be toxic in this study are close to those which may be injected into fish as a component of various vaccines against bacterial fish diseases. Hence, the formalin content in fish vaccines may well cause mortality under certa

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00670.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.The attachment ofVibriopathogens to cells of rainbow trout,Oncorhynchus mykiss(Walbaum), was studied by use of species‐specific monoclonal antibodies and indirect FITC‐ immunofluorescence microscopy.Vibrio anguillarum, V. ordaliiandV. parahaemolyticusattached to cultured cells of rainbow trout gonads, various tissues of cryostat sections of whole fish, and smears of gills, intestine, buccal mucosa and skin. The attachment was inhibited by prior incubation of bacteria with monoclonal antibodies at titres of 1:32, or less. OtherVibriopathogens used in this study did not attach to any trout cells. The research provides approaches to study the mechanisms of bacterial attachment in the onset ofVibrioinfecti

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00671.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.tb00672.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.tb00673.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.tb00674.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.tb00675.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY