No abstract

A monoclonal antibody-based flow-through immunoassay (FTA) was developed using a nitrocellulose membrane placed on the top of adsorbent pads enclosed in a plastic cassette with a test zone at the center. The FTA could be completed within 10 min. Clear purple dots against a white background indicated the presence of Aphanomyces (A.) invadans. The FTA limit of detection was 7 µg/mL for A. invadans compared to 56 µg/mL for the immunodot. FTA and polymerase chain reaction (PCR) could detect A. invadans in fish tissue homogenates at a 10-11 dilution compared to a 10-8 dilution by immunodot. In fish suffering from natural cases of epizootic ulcerative syndrome (EUS) collected from Mangalore, India, FTA and PCR could detect A. invadans in 100% of the samples compared to 89.04% detected by immunodot. FTA reagents were stable and produced expected results for 4 months when stored at 4~8℃. This rapid test could serve as simple and cost-effective on-site screening tool to detect A. invadans in fish from EUS outbreak areas and in ports during the shipment of live or frozen fish.

not availableBangladesh J. Zool. 45(2): 189-192, 2017

Background: Vibrio anguillarum is one of the major pathogen causing economic loss in the aquaculture industry. And, most of the microorganisms will use biofilm strategy for their survival in the host. Hence, less effectiveness of antibiotic and free cell (whole cell) vaccine may be observed in the aquaculture practice. Therefore the developed vaccine should be the mirror image of pathogen molecule, in regard; the present study was carried out to standardize the nutrient requirement for optimum biofilm production and antigen expression of biofilm and free cells of Vibrio anguillarum. Also, to identify the deferentially expressed protein in the biofilm mode. Methods: Culture conditions were optimized for the maximum biofilm production of V. anguillarum on chitin flakes as a substrate in nutrient restricted conditions. Through proteomic approach such as SDS PAGE was conducted to know the protein profile of biofilm and free cells of V. anguillarum and further, nanoLC-MS/MS was used to identify the differentially expressed protein in the biofilm of V. anguillarum. Result: Maximum biofilm production was observed on the 3rd day on 0.1% TSB concentration supplemented with 0.3% chitin flakes and 2% NaCl. Significant changes in the antigen expression of biofilm of V. anguillarum were observed in SDS PAGE and it revealed that in the biofilm mode, three new novel proteins were expressed and about ten proteins repressed as compared to that of free cell counterpart.