Experimental bacteriophage-mediated virulence in strains of Vibrio harveyi

Abstract

Vibriosis is a major disease problem in prawn aquaculture. Until now there has been no clear explanation why some strains of Vibrio are pathogenic, while others are not. This study demon-

Virulence Changes to Harveyi Clade Bacteria Infected with Bacteriophage from Vibrio owensii

“…Virulence factors encoded on bacteriophages may confer a wide range of traits to their hosts including toxin production and immunity to superinfection [18]. The involvement of bacteriophage in the virulence of V. harveyi has been documented previously by several authors [14,16,21]. One strain of V. campbellii (ACMM 642) originally reported as V. harveyi and one of the new species of V. owensii (47666-1) (previously V. harveyi 47666-1) have been shown to cause devastating disease in prawns in northern Australia [7].…”

“…One strain of V. campbellii (ACMM 642) originally reported as V. harveyi and one of the new species of V. owensii (47666-1) (previously V. harveyi 47666-1) have been shown to cause devastating disease in prawns in northern Australia [7]. A bacteriophage VHML from V. campbellii 642 was confirmed to confer virulence to naïve strains of V. harveyi [14]. While it was reported that V. owensii strain 47666-1 was more virulent than strain ACMM 642, causing 100 % mortality to Penaeus monodon larvae at 10 2 CFU ml -1 [13], there is no information yet to confirm whether a bacteriophage in this species confers virulence.…”

“…The mixed protein samples were then diluted with equal volume of SDS reducing buffer, mixed, boiled at 100°C for 5 min and used immediately in SDS-PAGE. One-dimensional poly-acrylamide gels of 7.5 cm length, using 0.75 mm spacers, with a 12 % separating gel and 4 % stacking gel were used and run by the method of [20] and [14]. A Bio-Rad Mini PROTEAN 3 Electrophoresis Cells (Bio Rad Laboratories, Regents Park, NSW, Australia) was used to electrophorese the gels with 19 SDS running buffer (pH 8.3).…”

“…The procedure for the preparation of CFS extract was modified from Harris and Owens [7] and Munro et al [14]. Sterile PYSS was inoculated with a stab from a strain of Harveyi clade bacteria from an overnight culture.…”

“…The modified method used by Muir [13], Harris and Owens [7] and Munro et al [14] was performed in bath challenge experiments with P. monodon nauplii. The seawater where the nauplii came from in the prawn hatchery was used instead of autoclaved seawater.…”