Ultrastructural localization of acid phosphatase activity in the small intestinal absorptive cells of postnatal rats

1981 ◽  
Vol 71 (4) ◽  
pp. 501-512 ◽  
Author(s):  
K. Ono ◽  
Y. Satoh
1992 ◽  
Vol 70 (7) ◽  
pp. 1377-1383 ◽  
Author(s):  
S. Pasqualini ◽  
F. Panara ◽  
M. Antonielli

Acid phosphatase activity of pine (Pinus pinea L.) roots was investigated in the presence or absence of the ectomycorrhizal fungus Tuber albidum Pico. Acid phosphatase activity was higher in mycorrhizal roots than in roots of uncolonized control plants. The optimum pH values for acid phosphatase were 3.5 and 5.0 for mycorrhizal roots and 5.0 for control roots. The acid phosphatase activity was inhibited by tartrate, fluoride, and molybdate ions, but a lower inhibition was exerted by orthophosphate. Mycorrhizal roots of pine possessed active acid phosphatases that hydrolyzed a wide variety of natural and synthetic phosphate esters. In particular, the enzyme was active against phytate and inorganic pyrophosphate. Two different Km values were estimated: about 0.22 mM and 2.78 mM at low and high substrate concentrations, respectively. The ultrastructural localization of acid phosphatase in mycorrhizal roots showed that the activity in the Hartig net was mainly localized in the plasmalemma of hyphae. Some lead phosphate precipitates were also observed in the middle lamella of the host cell. Key words: Pinus pinea, Tuber albidum, acid phosphatase, ectomycorrhiza, histochemical localization.


1974 ◽  
Vol 22 (12) ◽  
pp. 1092-1104 ◽  
Author(s):  
ATSUSHI KOMIYAMA ◽  
SAMUEL S. SPICER

Bone marrow basophils incubated in Gomori medium at pH 6.0-6.8 exhibited strong acid phosphatase activity suggestive of a potential role in endocytosis in one-third of the cytoplasmic granules and also in Golgi elements. Buffy coat basophils contained about one-third as many reactive granules. Reaction product was confined to the threadlike component of the larger granules predominant in early basophils and was absent from the denser-type granules predominant in late basophils. In centrioles of basophils acid phosphatase appeared localized between triplet fibers. Reactivity with the Gomori medium was diminished at pH 5.0, absent at pH 8.0 and only slightly decreased with p-nitrophenyl phosphate as substrate. Basophils incubated in Barka-Anderson medium at pH 5.0-6.8 revealed light acid phosphatase activity in the Golgi lamellae but essentially none in cytoplasmic granules. Tris-maleate buffer of the Barka-Anderson medium replacing the sodium acetate of the Gomori medium inhibited the reactivity in the granules. Incubation in media containing NaF, or lacking substrate, eliminated the heavy precipitates in granules and Golgi elements but yielded light, nonenzymatic lead staining in Golgi and tubulovesicular structures and atypical granules present only in buffy coat basophils.


1984 ◽  
Vol 17 (4) ◽  
pp. 371-377 ◽  
Author(s):  
INMACULADA SÁNCHEZ-AGUAYO ◽  
JOSEFINA HIDALGO ◽  
FELIPE CORTES ◽  
JOSE LUIS LÓPEZ-CAMPOS

1981 ◽  
Vol 47 (1) ◽  
pp. 77-89
Author(s):  
R. Deltour ◽  
S. Fransolet ◽  
R. Loppes

The nucleus of growing root cells Zea mays contains a high concentration of inorganic phosphate. In order to verify whether this high nuclear Pi concentration is correlated with the metabolic activity of the nucleus, the Pi has been visualized in root cells of maize embryos at the electron-microscope level during 2 different periods which are both characterized by a spectacular reactivation of the nuclear metabolism, i.e. the early germination and the period of recovery following a thermal treatment given to the seeds after 48 h of germination. In both situations the Pi concentration increased in the nucleus during its reactivation. To verify whether the high nuclear Pi concentration could be of endogenous origin, the phosphatase activities were measured in crude extracts of root tissues during nuclear reactivation. The specific activity was optimal at pH 4.5 and was shown to increase with cellular reactivation. The ultrastructural localization of acid phosphatase activity showed that Pi may be produced at 3 distinct sites: plasmalemma, vacuoles and most probably nucleus itself. High acid phosphatase activities were found in nuclei displaying a high metabolism. Taking these results and previous data into account, we suggest that a correlation may exist between the rate of nuclear transcription, the level of nuclear acid phosphatase activity and the nuclear Pi accumulation.


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