Premium
NADPH‐oxidase activity: the probable source of reactive oxygen intermediate generation in hemocytes of the gastropod Lymnaea stagnalis
Author(s) -
Adema C.M.,
DeutekomMulder E.C.,
Knaap W.P.W.,
Sminia T.
Publication year - 1993
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.54.5.379
Subject(s) - lymnaea stagnalis , nadph oxidase , respiratory burst , biology , zymosan , oxidase test , phagocytosis , reactive oxygen species , biochemistry , snail , enzyme , superoxide , cytosol , microbiology and biotechnology , ecology , in vitro
Abstract Macrophage‐like defense cells (hemocytes) of the pond snail Lymnaea stagnalis generate reactive oxygen intermediates (ROIs) upon contact with non‐self, following kinetics similar to those of ROI production by mammalian leukocytes during respiratory burst. In this study, several inhibitors of NADPH‐oxidase, the key enzyme of the respiratory burst in mammalian phagocytes, were tested for their effect on oxidative activities [as demonstrated by nitroblue tetrazolium (NBT) reduction and luminol‐dependent chemiluminescence (LDCL)] of phagocytosing snail hemocytes. In the presence of di‐ phenylenc iodonium, zymosan‐stimulated hemocytes of L. stagnalis failed to reduce NBT and showed a markedly reduced LDCL response. Also, compounds that prevent assembly of functional NADPH‐oxidase complexes in activated mammalian cells were effective; preincubation of hemocytes with 1,4‐naphthoquinone inhibited the LDCL response and NBT reduction upon phagocytic stimulation. Furthermore, coincubation but not preincubation with five different catechol‐like phenols inhibited oxidative activities of zymosan‐stimulated hemocytes. These results imply similarities in composition and regulation of the ROI‐generating mechanisms of both mammalian and snail defense cells. It is postulated that in L. stagnalis hemocytes, (1) NADPH‐oxidase activity is responsible for ROI production, (2) an active NADPH‐oxidase enzyme complex has to be assembled from putative cytosolic and membrane‐associated components, and (3) continuous replacement of active NADPH‐oxidase enzyme complexes is necessary to sustain respiratory burst‐like oxidative activities during interactions with non‐self.