Action of echinochrome in the innate immune response of the sea urchin Lytechinus variegatus (Lamarck, 1816)

Abstract

Echinocrome is a naftochinonic pigment found in interior granules of red sphere cells, a coelomocyte type of sea urchins Lytechinus variegatus. This cell have been considered as a biomarker due to its increase number in different conditions of stress, such as domestic residues contamination or the temperature increase and this was also observed by other researcher groups. Due to its red pigmentation, its observation becomes easy without the use of specialized drugs or equipments. Echinochrome, which is considered an oxygen transporter, acts either on oxidation or anti-oxidation of structures, acting as an oxidant of a reversible oxide-reduction system and it is active against many gram-negative and gram-positive bacteria in the level of 50 µg/ml. Thus, it is present in infections as bactericidal agent and as coagulant, acting in the formation of complexes that act in different physiological moments. The present project aims to correlate the echinocrome with innate immune process, through different levels (50 and 100 µg/ml) in quimiotatic and phagocytic activities of phagocytic amebocytes of the sea urchin Lytechinus variegatus. For that, it will be used the Boyden chamber protocol for the queimiotatic assays and, for phagopcytic assays I will be used phagocytic indexes, phagocytic capacity and germicidal capacity of these cells facing Escherichia colli (LPS) and yeast suspension (Saccharomyces cerevisiae). Results obtaines would be useful to elucidate still unknown functions of this naftoquinon, and thus to help to understand the innate immune response in echinoderms, besides the better evaluation of the animals, once granules containing echinocrome are degranulated in minimal stress conditions.