In vitro phenoloxidase activity in the blood of Ciona intestinalis and other ascidians

Ultrastructural aspects of naturally occurring wound in the tunic of two ascidians: Ciona intestinalis and Styela plicata (Tunicata)

“…The massive increment in the number of haemocytes present at the site of wounding after the injection of histamine into the tunic, is consistent with the role that this molecule may play in the regulation of Styela immunity, involving the selective recruitment of effector cells into the tissues (de Barros et al, 2007;García-García et al, 2014). Moreover, the prophenoloxidase system is activated on the wound to produce melanization (Jackson et al, 1993;Johansson and Söderhall, 1989). The prophenoloxidase system is a proteolytic enzyme cascade which recognizes minuscule amounts of cell wall products from microorganisms (lipopolysaccharide, peptidoglycan and glucans) and responds to the microbes by activation of the system and the subsequent generation of immune factors (Cerenius et al, 2008).…”

Hemocytes Release Phenoloxidase upon Contact Reaction, an Allogeneic Interaction, in the Ascidian Halocynthia roretzi.

“…This cascade is provoked by microbial glycans and eventually triggers a surge of active phenoloxidase (1,17,28). Recently the activity of phenoloxidase has been detected in the hemocytes of someother marine invertebrates including several ascidians (15,29), although the biological significance of the enzyme has yet to be clarified.…”

Upregulated transcription of phenoloxidase genes in the pharynx and endostyle of Ciona intestinalis in response to LPS

“…The ascidian POs are copperdependent orthodiphenoloxidases (Kahn, 1985;Sugumaran et al, 1988) that were at first identified by histochemical reaction in the tunic hemocytes (Barrington and Thorpe, 1968), suggesting a quinone-tanning system involved in the production of tunic scleroprotein (Chaga, 1980). Circulating hemocytes from naïve ascidians can exert in vitro PO-dependent cytotoxic activity versus erythrocytes and tumor cell lines (Cammarata et al, 1997;Arizza et al, 2011), whereas LPS inoculation activates the proPO pathway, and enhanced PO activity (Jackson et al, 1993;Cammarata and Parrinello, 2009). In non-fusion reaction of colonial ascidians, the enzyme mediates the formation of the cytotoxic foci along the contacting regions of genetically incompatible colonies (Hirose et al, 1990;Ballarin et al, 1998;Shirae and Saito, 2000;Shirae et al, 2002;Cima et al, 2004;Zaniolo et al, 2006).…”