Plasmodium falciparum: discovery of peroxidase active organelles.
Staining with 3,3' diaminobenzidine tetrahydrochloride (DAB) is a common method used for the detection of peroxidases. Using this histochemical staining method in conjunction with transmission electron microscopy, we observed oxidation of DAB that was localized to a discrete set of organelles displaying morphological similarity to small (75-90 nm diameter) versions of higher eukaryotic microbodies or peroxisomes. These single membrane bounded organelles were characterized by an asymmetrical matrix capable of oxidizing DAB to an electron dense inclusion. Oxidation of DAB was further found to be dependent upon hydrogen peroxide (H2O2) as a substrate. Given a lack of peroxisomal import proteins and enzymes, it is unlikely that these represent conventional peroxisomes. Rather, they likely represent specialized organelles containing endogenous peroxidase or pseudo-peroxidase activity.
McIntosh
Michael T
MT
Department of Internal Medicine, Yale University School of Medicine, 333 Cedar Street, P.O. Box 20822, New Haven, CT 06520-8022, USA.
Elliott
David A
DA
Joiner
Keith A
KA
D015100:3,3'-Diaminobenzidine / Q000378:metabolism; D000818:Animals; D006651:Histocytochemistry; D006861:Hydrogen Peroxide / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D015388:Organelles / Q000201:enzymology* / Q000648:ultrastructure; D010544:Peroxidases / Q000378:metabolism*; D010963:Plasmodium falciparum / Q000201:enzymology* / Q000648:ultrastructure*
D015100:3,3'-Diaminobenzidine; D006861:Hydrogen Peroxide; D010544:Peroxidases