ovalbumin and Fish-Diseases

Oral delivery of DNA vaccines represents a promising vaccinating method for fish. Recombinant yeast has been proved to be a safe carrier for delivering antigen proteins and DNAs to some species in vivo. However, whether recombinant yeast can be used to deliver functional DNAs for vaccination to fish is still unknown. In this study, red crucian carp (Carassius auratus) was orally administrated with recombinant Saccharomyces cerevisiae harboring CMV-EGFP expression cassette. On day 5 post the first vaccination, EGFP expression in the hindgut was detected under fluorescence microscope. To further study whether the delivered gene could induce specific immune responses, the model antigen ovalbumin (OVA) was used as immunogen, and oral administrations were conducted with recombinant S. cerevisiae harboring pCMV-OVA mammalian gene expression cassette as gene delivery or pADH1-OVA yeast gene expression cassette as protein delivery. Each administration was performed with three different doses, and the OVA-specific serum antibody was detected in all the experimental groups by western blotting and enzyme-linked immunosorbent assay (ELISA). ELISA assay also revealed that pCMV-OVA group with lower dose (pCMV-OVA-L) and pADH1-OVA group with moderate dose (pADH1-OVA-M) triggered relatively stronger antibody response than the other two doses. Moreover, the antibody level induced by pCMV-OVA-L group was significantly higher than pADH1-OVA-M group at the same serum dilutions. All the results suggested that recombinant yeast can be used as a potential carrier for oral DNA vaccines and would help to develop more practical strategies to control infectious diseases in aquaculture.

Topics: Animals; Antibodies, Viral; Cytomegalovirus; Cytomegalovirus Infections; Fish Diseases; Goldfish; Green Fluorescent Proteins; Ovalbumin; Saccharomyces cerevisiae; Vaccines, DNA; Viral Vaccines

An antigen-capture enzyme-linked immunosorbent assay (ELISA) was developed to detect and measure isometamidium chloride in the plasma of Oncorhynchus tshawytscha and O. mykiss. Isometamidium-ovalbumin conjugate and anti-isometamidium antibodies were used to coat polystyrene plates. The peroxidase saturation technique was used to optimize the coating antigen concentration; it demonstrated low affinity of the isometamidium-ovalbumin conjugate but high affinity of the anti-isometamidium antibodies for polystyrene surface sites. The optimal conditions of antiisometamidium antibodies to coat plates was at pH 7.3 and a 1:1000 dilution (0.0012 mg ml(-1) protein). The ELISA was sensitive as it detected 0.0006 mg ml(-1) of isometamidium in fish plasma. Isometamidium diluted with saline could not be detected at concentrations less than 0.05 mg ml(-1). The results indicate that this ELISA is much more sensitive when isometamidium is bound to plasma than unbound isometamidium in saline.

Topics: Animals; Chromatography, DEAE-Cellulose; Enzyme-Linked Immunosorbent Assay; Fish Diseases; Immunization; Immunoelectrophoresis; Oncorhynchus mykiss; Ovalbumin; Phenanthridines; Salmon; Sensitivity and Specificity; Thyroglobulin; Trypanocidal Agents

Protein-polysaccharide conjugate was prepared as a functional biopolymer using protein and polysaccharide via a Maillard-type reaction. Ovalbumin and lysozyme were conjugated with galactomannan under controlled heating and humidity conditions. The antioxidant effect of ovalbumin and the antimicrobial activity of lysozyme were enhanced by the glycosylation. The emulsifying properties of the egg protein were also significantly improved by the modification. The increase in lipid affinity due to the conjugation resulted in the enhancement of the radical scavenging ability of ovalbumin. The effectiveness of lysozyme and its glycosylated derivative in restricting the activity of a Gram-negative pathogen, Edwardsiella tarda in fish was also investigated.

Topics: Animals; Anti-Bacterial Agents; Antioxidants; Biopolymers; Carps; Crystallization; Edwardsiella; Electrophoresis, Polyacrylamide Gel; Emulsions; Fish Diseases; Galactose; In Vitro Techniques; Lethal Dose 50; Maillard Reaction; Mannans; Muramidase; Mutagens; Ovalbumin; Rats