551
Owens 2000 ; Austin et al. 2003 ) and bacteriocin-like substances (BLIS; Prasad
et al. 2005 ). The Vibrio harveyi myovirus like (VHML) phage enhanced virulence
of V. harveyi to Atlantic salmon and enhanced haemolytic activity (Austin et al.
2003 ). Using a culture that was pathogenic for salmonids, it was revealed that BLIS
was inhibitory to four other isolates of the same taxon and to representatives of
other vibrios, including V. parahaemolyticus . The BLIS was extracted from cellfree supernatants, and determined to be an unique protein of ~32 kDa molecular
weight (Prasad et al. 2005 ).
Comparatively high doses of the organism labeled as V. trachuri were required to
cause disease in Japanese horse mackerel. Thus using 36.8 g fi sh at a water temperature of 26 °C, 1.1 × 10
8 cells/fi sh caused 100 % mortalities within 24 h of i.p. injection. A dose of 1.1 × 10
7 cells/ml led to 50 % mortalities within 4 days. By immersion
in 3.6 × 10
7 cells/ml for 2 min, 100 % mortalities ensued within 3 days (Iwamoto
et al. 1995 ). The disease signs mimicked those on naturally infected fi sh, i.e. erratic
swimming and melanosis. Incidentally, the organism failed to infect red sea bream.
The question about the host response to infection by V. harveyi was addressed in
turbot ( Psetta maxima ) model whereby SSH identifi ed immune gene expression (to
the infection) by a major histocompatibility complex class 1a gene, and a heat shock
protein 70 gene. This may be an important component in the immune system insofar
as a rapid transcriptional upregulation after infection may be important to fi sh survival (Zhang et al. 2011c ). Also, some signaling molecules were found in cDNA
libraries, and included src-family tyrosine kinase SCK, sgk-1 serine- threonine protein kinase and amyloid precursor-like protein 2 (Wang et al. 2008 ).
Disease Control
Vaccine Development Vaccine development programmes have not been especially successful in the past, although this situation appears to be slowly changing
(Xu et al. 2009 ) with the realisation that subcellular components, e.g. ECPs and
OMPs, may elicit an immune response (Arijo et al. 2008 ). A whole cell preparation,
which was applied to barramundi (Lates calcarifer) by i.p. injection, anal intubation
and immersion, led to antibody production thereby demonstrating that fi sh could
respond to vaccination (Crosbie and Nowak 2004 ). By expressing the HL 1 gene,
which encodes the haemolysin from V. harveyi, in yeast (Saccharomyces cerevisiae) , the protein (= haemolysin) was expressed on the cell surface and was active
against fl ounder erythrocytes. Moreover, serum from fl ounder that had received the
live modifi ed yeast cells by i.p. injection revealed haemolytic activity. Challenge
experiments demonstrated that fl ounder and turbot were protected soon after administration of yeast and then exposure to a virulent culture of V. harveyi (Zhu et al.
2006 ). VhhP2, which is an OMP, has been used successfully as a sub-unit vaccine
suspended in Bacillus sp. B187 as adjuvant with success when injected i.p. in 100 μl
amounts in Japanese fl ounder followed by a booster 20 days later, and challenge
after a further 14 days. A live recombinant vaccine, which presents VhhP2, was
Vibrio harveyi (= V. carchariae = V. trachuri)
Owens 2000 ; Austin et al. 2003 ) and bacteriocin-like substances (BLIS; Prasad
et al. 2005 ). The Vibrio harveyi myovirus like (VHML) phage enhanced virulence
of V. harveyi to Atlantic salmon and enhanced haemolytic activity (Austin et al.
2003 ). Using a culture that was pathogenic for salmonids, it was revealed that BLIS
was inhibitory to four other isolates of the same taxon and to representatives of
other vibrios, including V. parahaemolyticus . The BLIS was extracted from cellfree supernatants, and determined to be an unique protein of ~32 kDa molecular
weight (Prasad et al. 2005 ).
Comparatively high doses of the organism labeled as V. trachuri were required to
cause disease in Japanese horse mackerel. Thus using 36.8 g fi sh at a water temperature of 26 °C, 1.1 × 10
8 cells/fi sh caused 100 % mortalities within 24 h of i.p. injection. A dose of 1.1 × 10
7 cells/ml led to 50 % mortalities within 4 days. By immersion
in 3.6 × 10
7 cells/ml for 2 min, 100 % mortalities ensued within 3 days (Iwamoto
et al. 1995 ). The disease signs mimicked those on naturally infected fi sh, i.e. erratic
swimming and melanosis. Incidentally, the organism failed to infect red sea bream.
The question about the host response to infection by V. harveyi was addressed in
turbot ( Psetta maxima ) model whereby SSH identifi ed immune gene expression (to
the infection) by a major histocompatibility complex class 1a gene, and a heat shock
protein 70 gene. This may be an important component in the immune system insofar
as a rapid transcriptional upregulation after infection may be important to fi sh survival (Zhang et al. 2011c ). Also, some signaling molecules were found in cDNA
libraries, and included src-family tyrosine kinase SCK, sgk-1 serine- threonine protein kinase and amyloid precursor-like protein 2 (Wang et al. 2008 ).
Disease Control
Vaccine Development Vaccine development programmes have not been especially successful in the past, although this situation appears to be slowly changing
(Xu et al. 2009 ) with the realisation that subcellular components, e.g. ECPs and
OMPs, may elicit an immune response (Arijo et al. 2008 ). A whole cell preparation,
which was applied to barramundi (Lates calcarifer) by i.p. injection, anal intubation
and immersion, led to antibody production thereby demonstrating that fi sh could
respond to vaccination (Crosbie and Nowak 2004 ). By expressing the HL 1 gene,
which encodes the haemolysin from V. harveyi, in yeast (Saccharomyces cerevisiae) , the protein (= haemolysin) was expressed on the cell surface and was active
against fl ounder erythrocytes. Moreover, serum from fl ounder that had received the
live modifi ed yeast cells by i.p. injection revealed haemolytic activity. Challenge
experiments demonstrated that fl ounder and turbot were protected soon after administration of yeast and then exposure to a virulent culture of V. harveyi (Zhu et al.
2006 ). VhhP2, which is an OMP, has been used successfully as a sub-unit vaccine
suspended in Bacillus sp. B187 as adjuvant with success when injected i.p. in 100 μl
amounts in Japanese fl ounder followed by a booster 20 days later, and challenge
after a further 14 days. A live recombinant vaccine, which presents VhhP2, was
Vibrio harveyi (= V. carchariae = V. trachuri)