Research Example (2)

When rabbits are injected with purified fish proteins, the rabbits recognize them as foreign substances and produce antibodies. This antibody binds to the injected protein but not to the others. A chromogenic/luminescent substrate is attached to the antibody, and the amount of binding is detected and measured as color or luminosity.

Immunochemical assay systems for yolk protein precursors:

The figure on the left shows the standard curve (luminance on the vertical axis and VtgAa concentration on the horizontal axis) and the serum dilution series (Male serum ○, serum containing VtgAa ●) of the chemoluminescence immunoassay system for the yolk protein precursor (synonymous with VtgAa = VgA) of mullet (Mugil cephalus). The higher the VtgAa, the higher the luminosity value, and antibodies don′t react with other contaminating seroproteins (male serum).

Example of measurement of yolk protein precursors:

The figure on the left shows the immunochemical measurement of three types of Vtg using mullet serum at various stages of sexual maturity. The vertical axis is Vtg concentration, and the horizontal axis is gonad weight per body weight (gonad body index: GSI). Early in sexual maturation, Vtg levels are low. When GSI exceeds 10% and Vtg levels tend to decrease as spawning approaches. Continuous monitoring of Vtg as a blood marker for maturity and egg maturation can predict the timing of spawning and hormone administrations.