Now showing items 1-3 of 3

    • Article

      Development of a polymerase chain reaction (PCR) assay targeted to the dnaJ gene of Vibrio harveyi, a bacterial pathogen in Asian seabass, Lates calcarifer 

      CMA Caipang, RV Pakingking Jr., MJS Apines-Amar, F Huyop & NB Bautista - Aquaculture, Aquarium, Conservation and Legislation, 2011 - Bioflux
      Partial sequence of the dnaJ gene of Vibrio harveyi, which was isolated from diseased juvenile Asian seabass, Lates calcarifer was identified. The partial sequence of dnaJ gene of V. harveyi was 447 bp and shared at least 77% identity at the nucleotide level with the dnaJ gene of other Vibrios. It was distinct from the dnaJ gene of other Vibrios but was closely related with the dnaJ gene of V. rotiferianus and V. campbellii having at least 90% nucleotide identity. PCR primers targeting this gene were designed to detect the pathogen in Asian seabass. The assay was specific to V. harveyi and the limit of detection was 100 pg of genomic DNA ml-1 or 100 fg of bacterial genomic DNA in a PCR reaction. This corresponded to a sensitivity of approximately 20 genome equivalents (GE) of V. harveyi. These results indicate that the dnaJ gene is a good candidate to develop primers for the PCR assay in detecting V.harveyi in fish.
    • Article

      Evidence of WSSV transmission from the rotifer (Brachionus plicatilis) to the black tiger shrimp (Penaeus monodon) postlarvae and means to control rotifer resting eggs using industrial disinfectants 

      V Corre Jr., J Faisan Jr., RJ Carton-Kawagoshi, BJ Elle, RF Traifalgar & CM Caipang - Aquaculture, Aquarium, Conservation and Legislation, 2012 - Bioflux
      Rotifers are considered possible vectors of the white spot syndrome virus (WSSV) and have been implicated in its recurrence in pond-cultured shrimp. However, direct evidence of the transmission and the pathogenicity of this virus from rotifers to shrimp has been lacking. In the present study, the pathogenicity of WSSV transmitted from infected rotifers (Brachionus plicatilis) to post larval black tiger shrimp (Penaeus monodon) was investigated. Results show that WSSV transmitted from infected rotifers to post-larval P. monodon caused an 82% cumulative mortality as compared to a 9% mortality in the non-infected control group. We also investigated the possibility of industrial disinfectants (sodium hypochlorite, granulated calcium hypochlorite and formalin) as possible means to inhibit the viability of rotifer resting eggs, considered a biological reservoir of WSSV in earthen ponds. Among the disinfectants that were tested, granulated calcium hypochlorite at 5 mg/L was the most effective. The present study provides direct evidence of the high pathogenicity of WSSV transmitted from rotifers to post larval P. monodon and shows the potential use of granulated calcium hypochlorite in pond disinfection. This treatment could be a promising strategy to inhibit the spread and recurrence of WSSV outbreaks in P. monodon culture.
    • Article

      Screening of vibriosis in Asian seabass, Lates calcarifer using loop-mediated isothermal amplification (LAMP) assay 

      CMA Caipang, RV Pakingking Jr. & MJS Apines-Amar - Human & Veterinary Medicine, 2012 - Bioflux Society
      The aim of this study was to standardize a loop-mediated isothermal amplification (LAMP) assay for the detection of Vibrio harveyi , the causative agent of vibriosis in Asian seabass, Lates calcarifer. The dnaJ gene of the bacterial pathogen was used as the target gene for the LAMP assay. It was optimized at an incubation time of 1 h at 63°C. The assay was highly specific for V. harveyi and did not cross-react with other bacterial pathogens offish. However, the assay was able to detect V. harveyi that was isolated from infected shrimps. The limit of detection of the LAMP assay was 40 pg of DNA mL-1 or 40 fg of the genomic DNA per LAMP reaction and was 10 times more sensitive than conventional PCR in detecting the bacterial pathogen from infected samples. The LAMP products can be quantified spectrophotometrically using hydroxynaphthol blue (HNB) dye and showed positive correlation with the amount of the pathogen. These results demonstrated that LAMP is a simple and sensitive detection technique that has potential application for routine diagnosis of vibrosis caused by V. harveyi in Asian seabass and other aquatic species.