TY - JOUR
T1 - Entamoeba histolytica
T2 - Ultrastructural localization of Ca2+-dependent nucleotidases
AU - Kobayashi, Seiki
AU - Takeuchi, Tsutomu
AU - Asami, Keizo
AU - Fujiwara, Tatsushi
N1 - Funding Information:
The authors thank Dr. Louis S. Diamond, Laboratory of Parasitic Diseases, National Institutes of Health, Bethesda, Maryland, U.S.A., for his generous gift of bovine serum. This study was supported in part by the research grants from the Ministry of Education, Japan, and from the School of Medicine, Keio University.
PY - 1982/10
Y1 - 1982/10
N2 - Localization of nucleotidases dependent on Ca2+ was investigated cytochemically in axenically cultivated trophozoites of Entamoeba histolytica, strain HM-1:IMSS, with an electron microscope. Ca2+-dependent ATPase (EC 3.6.1.3) activity was found on the plasma membrane and on the inner surface of the limiting membrane of a few cytoplasmic vacuoles. Ca2+-dependent ADPase, Ca2+-dependent thiamine pyrophosphatase, and acid phosphatase (EC 3.1.3.2) activities were detected on the inner surface of the limiting membrane of most of the cytoplasmic vacuoles but not on the plasma membrane. Cytoplasmic vacuoles with these enzymatic activities seemed similar in morphological characteristics. Moreover, the reaction product formed by Ca2+-dependent ADPase, Ca2+-dependent thiamine pyrophosphatase and acid phosphatase was demonstrable on the inner surface of the limiting membrane of vacuoles containing ingested red blood cells. The reaction product formed by these enzymes was also observed on the periphery of ingested red blood cells. The findings suggest that cytoplasmic vacuoles with these enzymatic activities are lysosomal in nature, probably phagolysosomes; therefore, the enzymes appear to be at least partially associated with primary lysosomes of E. histolytica.
AB - Localization of nucleotidases dependent on Ca2+ was investigated cytochemically in axenically cultivated trophozoites of Entamoeba histolytica, strain HM-1:IMSS, with an electron microscope. Ca2+-dependent ATPase (EC 3.6.1.3) activity was found on the plasma membrane and on the inner surface of the limiting membrane of a few cytoplasmic vacuoles. Ca2+-dependent ADPase, Ca2+-dependent thiamine pyrophosphatase, and acid phosphatase (EC 3.1.3.2) activities were detected on the inner surface of the limiting membrane of most of the cytoplasmic vacuoles but not on the plasma membrane. Cytoplasmic vacuoles with these enzymatic activities seemed similar in morphological characteristics. Moreover, the reaction product formed by Ca2+-dependent ADPase, Ca2+-dependent thiamine pyrophosphatase and acid phosphatase was demonstrable on the inner surface of the limiting membrane of vacuoles containing ingested red blood cells. The reaction product formed by these enzymes was also observed on the periphery of ingested red blood cells. The findings suggest that cytoplasmic vacuoles with these enzymatic activities are lysosomal in nature, probably phagolysosomes; therefore, the enzymes appear to be at least partially associated with primary lysosomes of E. histolytica.
KW - ATPase (EC 3.6.1.3)
KW - Acid phosphatase (EC 3.1.3.2)
KW - Apyrase (EC 3.6.1.5)
KW - Ca-dependence
KW - Cytochemistry
KW - Electron microscopy
KW - Entamoeba histolytica
KW - Lysosome
KW - Membrane, plasma
KW - Nucleoside diphosphatase (EC 3.6.1.6)
KW - Protozoa, parasitic
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U2 - 10.1016/0014-4894(82)90128-X
DO - 10.1016/0014-4894(82)90128-X
M3 - Article
C2 - 6182018
AN - SCOPUS:0020448652
VL - 54
SP - 202
EP - 212
JO - Experimental Parasitology
JF - Experimental Parasitology
SN - 0014-4894
IS - 2
ER -