Localization of Putative Haemoglobin by Immunogold Staining in Artemia
The distribution of immunoreactive haemoglobin in Artemia was sought by means of the immunogold technique and electron microscopy with primary antibodies raised against HbII.
Before affinity purification of the primary antibody, gold deposits were found in a number of regions that would not have been regarded as primary candidates for haemoglobin localization. Most conspicuously staining was the cuticular region of the cyst wall between the inner and outer cuticular membranes. Other positive regions were the developing exoskeletal region of the encysted embryo; the naupliar exoskeleton; and the microvillous surface of cells lining the digestive tract.
Primary antibody purified by elution from immobilised haemoglobin bound less to the above structures but more to intercellular spaces interpreted as haemocoel. This would be compatible with a purification of the antibody from a contaminant fraction. However the localization in the unexpected structures was supported by positive and negative controls and may indicate the incorporation of antigenic fragments recognized by one fraction of the antibody. Since significant synthesis of globin does not occur in the encysted embryo, the cyst wall cuticular globin immunoreactivity may be of maternal origin.