NADPH-oxidase activity: the probable source of reactive oxygen intermediate generation in hemocytes of the gastropod Lymnaea stagnalis.
J Leukoc Biol
; 54(5): 379-83, 1993 Nov.
Article
en En
| MEDLINE
| ID: mdl-8228616
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 diphenylene 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.
Buscar en Google
Base de datos:
MEDLINE
Asunto principal:
Especies Reactivas de Oxígeno
/
Hemocitos
/
Lymnaea
/
NADH NADPH Oxidorreductasas
Idioma:
En
Revista:
J Leukoc Biol
Año:
1993
Tipo del documento:
Article