Ultrastructural localization of phosphatases in the testes of the domestic fowl: Acid phosphatase and thiamine pyrophosphatase

1982 ◽  
Vol 74 (2) ◽  
pp. 157-169 ◽  
Author(s):  
V. K. Gunawardana ◽  
H. Mayahara ◽  
K. Ogawa
Keyword(s):  
Acid Phosphatase ◽  
Domestic Fowl ◽  
Ultrastructural Localization ◽  
Thiamine Pyrophosphatase

A deletion that includes the segment coding for the signal peptidase cleavage site delays release of Saccharomyces cerevisiae acid phosphatase from the endoplasmic reticulum

1986 ◽  
Vol 6 (2) ◽  
pp. 723-729
Author(s):  
R Haguenauer-Tsapis ◽  
M Nagy ◽  
A Ryter
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Endoplasmic Reticulum ◽  
Acid Phosphatase ◽  
Cleavage Site ◽  
Ultrastructural Localization ◽  
Signal Peptidase ◽  
Multicopy Plasmid ◽  
Wild Type ◽  
Sugar Chains ◽  
Pho5 Gene

We studied ultrastructural localization of acid phosphatase in derepressed Saccharomyces cerevisiae cells transformed with a multicopy plasmid carrying either the wild-type PHO5 gene or a PHO5 gene deleted in the region overlapping the signal peptidase cleavage site. Wild-type enzyme was located in the cell wall, as was 50% of the modified protein, which carried high-mannose-sugar chains. The remaining 50% of the protein was active and core glycosylated, and it accumulated in the endoplasmic reticulum cisternae. The signal peptide remained uncleaved in both forms. Cells expressing the modified protein exhibited an exaggerated endoplasmic reticulum with dilated lumen.

Formation of chlamydospores in Gilbertella persicaria

1981 ◽  
Vol 59 (5) ◽  
pp. 908-928 ◽  
Author(s):  
Martha J. Powell ◽  
Charles E. Bracker ◽  
David J. Sternshein
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Acid Phosphatase ◽  
Light And Electron Microscopy ◽  
Multivesicular Bodies ◽  
Marker Enzyme ◽  
Transparent Layer ◽  
Thiamine Pyrophosphatase ◽  
Gilbertella Persicaria

The cytological events involved in the transformation of vegetative hyphae of the zygomycete Gilbertella persicaria (Eddy) Hesseltine into chlamydospores were studied with light and electron microscopy. Thirty hours after sporangiospores were inoculated into YPG broth, swellings appeared along the aseptate hyphae. Later, septa, traversed by plasmodesmata, delimited each end of the hyphal swellings and compartmentalized these hyphal regions as they differentiated into chlamydospores. Nonswollen regions adjacent to chlamydospores remained as isthmuses. Two additional wall layers appeared within the vegetative wall of the developing chlamydospores. An alveolate, electron-dense wall formed first, and then an electron-transparent layer containing concentrically oriented fibers formed between this layer and the plasma membrane. Rather than a mere condensation of cytoplasm, development and maturation of the multinucleate chlamydospores involved extensive cytoplasmic changes such as an increase in reserve products, lipid and glycogen, an increase and then disappearance of vacuoles, and the breakdown of many mitochondria. Underlying the plasma membrane during chlamydospore wall formation were endoplasmic reticulum, multivesicular bodies, vesicles with fibrillar contents, vesicles with electron-transparent contents, and cisternal rings containing the Golgi apparatus marker enzyme, thiamine pyrophosphatase. Acid phosphatase activity was localized cytochemically in a cisterna which enclosed mitochondria and in vacuoles which contained membrane fragments. Tightly packed membrane whorls and single membrane bounded sacs with finely granular matrices surrounding vacuoles were unique during chlamydospore development. Microbodies were rare in the mature chlamydospore, but endoplasmic reticulum was closely associated with lipid globules. As chlamydospores developed, the cytoplasm in the isthmus became highly vacuolated, lipid globules were closely associated with vacuoles, mitochondria were broken down in vacuoles, unusual membrane configurations appeared, and eventually the membranes degenerated. Unlike chlamydospores, walls of the isthmus did not thicken, but irregularly shaped appositions containing numerous channels formed at intervals on the inside of these walls. The pattern of cytoplasmic transformations during chlamydospore development is similar to events leading to the formation of zygospores and sporangiospores.

Localization of Enzymes in Certain Secretory Cells of Helix Tentacles

1964 ◽  
Vol s3-105 (69) ◽  
pp. 49-60
Author(s):  
NANCY J. LANE
Keyword(s):  
Alkaline Phosphatase ◽  
Acid Phosphatase ◽  
Cell Types ◽  
Secretory Cells ◽  
Oval Cells ◽  
Cytoplasmic Localization ◽  
Cell Organelles ◽  
Distinct Cell ◽  
Thiamine Pyrophosphatase ◽  
Ultrastructural Appearance

Secretory cells in the optic tentacles of the snails, Helix aspersa and H. pomatia, have been investigated for the cytoplasmic localization of certain enzymes. The collar cells, considered to be neurosecretory, and the lateral oval cells, were those examined. Acid phosphatase activity is found in the cytoplasm of both cells, in scattered spheroids called the β-bodies. This enzymatic activity indicates that the β-bodies may be lysosomes, as does their ultrastructural appearance. In the 2 cell types, the activity of both alkaline phosphatase and thiamine pyrophosphatase is localized in crescentic bodies considered to correspond to the Golgi lamellae, and in some of the β-bodies. The latter enzyme also exists in the cortices of the α-bodies which, like the β-bodies, are lipid-containing globules. The activity of both cytochrome oxidase and succinate dehydrogenase is found, not only in granules, rods, and filaments interpreted as the mitochondria, but also on the cortices of some or all of the β-bodies. It is concluded that in invertebrates, the lipochondria may be the sites of activity of many different enzymes which in vertebrates are restricted to distinct cell organelles.

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