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  • 1
    Digitale Medien
    Digitale Medien
    Sites of acid phosphatase in the differentiating root protophloem of Nymphoides peltata (S.G. Gmel.) O. Kuntze. (1981)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 4 (1981), S. 0 
    Details
    ISSN: 1365-3040
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Abstract Sites of acid-phosphatase activity were found in the differentiating root protophloem of Nymphoides peltata by lead-salt and by azo-dye methods. Different substrates revealed different subcellular locations of the enzyme. The substrates β-glycerophosphate (β-GP) and naphthol ASBI phosphate revealed enzyme activity at similar sites within the sieve element. These sites included plasmodesmata, dictyosomes and small vacuoles in the cytoplasm. The substrate p-nitrophenylphosphate (p-NPP), however, revealed additional sites of acid-phosphatase activity which were not detectable by either naphthol ASBI phosphate or β-GP. For example, the inner region of the wall in mature sieve elements showed conspicuous acid-phosphatase activity only when p-NPP was used as substrate. The significance of the different locations of acid phosphatase within the sieve element is discussed.The convoluted ER, characteristic of immature sieve elements of N. peltata, failed to show acid-phosphatase activity whichever substate was used. By contrast, the stacked ER found in the parietal layer of mature sieve elements showed prominent acid-phosphatase activity regardless of the substrate used. The demonstration of acid-phosphatase activity in the stacked ER, and by both lead-salt and azo-dye methods, suggests that this organelle is a true site of acid-phosphatase activity.The onset of acid-phosphatase activity in the ER in later stages of sieve-element differentiation is compatible with the view that stacked ER plays a role in the final autolysis of the sieve-element protoplast.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1365-3040.1981.tb00832.x
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  • 2
    Digitale Medien
    Digitale Medien
    Acid phosphatase activity and cell death in mouse thymus (1980)
    Springer
    Histochemistry and cell biology 65 (1980), S. 173-179 
    Details
    ISSN: 1432-119X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of acid phosphatase activity in the thymus of young (8 week) and old (42 week) mice is presented. In 8 week old mice acid phosphatase positive cells represent 1.27±0.13% of the total population whereas in 42 week old mice, showing involution of the thymus, acid phosphatase positive cells represent 2.40±0.17% of the total population. Loci of free acid phosphatase activity have been interpreted as sites of cell lysis and death. This has been confirmed at electron microscope level where free acid phosphatase has been demonstrated in the cytoplasm of lysing thymic lymphocytes. Vacuolar sites of acid phosphatase activity have been demonstrated in macrophages which appear to dispose of the lymphocytes. Extensive autophagic activity occurs in the epithelial reticular cells. The role of acid phosphatase in thymic lymphocyte deletion and in the tissue dynamics of the thymus is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00493166
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  • 3
    Digitale Medien
    Digitale Medien
    The fine structure of the planarianPolycelis tenuis ijima (1973)
    Springer
    Protoplasma 78 (1973), S. 223-241 
    Details
    ISSN: 1615-6102
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The fine structure of the pharynx is presented and demonstrates that the pharyngeal epithelial system is a continuous one. The epithelial lining of the pharyngeal cavity with its characteristic fibrous secretory bodies merges with the outer pharyngeal epithelium at the point of anchorage of the pharynx. A few of these cells are insunk, the nuclei occurring beneath the underlying muscular layers. The nature of the outer epithelium changes towards the free end of the pharynx; the cells become ciliated and in contents come to resemble the inner epithelium which it joins at the tip. The gut cells merge at a transitional zone with the inner pharyngeal epithelium and at this point both bear microvilli and contain rod-shaped apical bodies. Some of these cells are also insunk. Towards the mouth the epithelium shows a greater degree of insinking and exhibits microapocrine secretion. Both inner and outer epithelia bear sense receptors which are concentrated at the lip. At the point of pharyngeal insertion, the sub-epithelial tissue resembles planarian parenchyma, but is rich in gland cells. These glands open on to the outer epithelium especially towards the free end of the pharynx.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01275693
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  • 4
    Digitale Medien
    Digitale Medien
    The fine structure of the planarianPolycelis tenuis Iijima (1974)
    Springer
    Protoplasma 79 (1974), S. 1-17 
    Details
    ISSN: 1615-6102
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The fine structure of the Minotian gland cell (spherical or granular club cell) and the phagocytic cell of the gastrodermis is described. The Minotian cells characteristically contain distinctive granules which are produced by the Golgi. Inclusion bodies containing membranous remains can also be found in the cytoplasm. The phagocytic cells bear groups of microvilli near adjacent junctions and have a much infolded basement membrane. Near the pharynx these cells contain the rod-shaped apical bodies found in the pharyngeal epithelium. Further into the intestine the cells more characteristically contain numerous phagocytic vacuoles and vacuolar dense bodies. After feeding, a consistent occlusion of the intestinal lumen has been observed. The columnar phagocytes have been shown to phagocytose cellular material and will also take up peroxidase and thorium oxide. The substances initially appear in the apical phagosomes. Acid phosphatase activity has been detected in the phagosomes after feeding. The enzyme is packaged in the Golgi and occurs in Golgi vacuoles and lysosomes of similar dimensions (morphologically vacuolar dense bodies). The fusion of lysosomes with phagosomes has been demonstrated histochemically.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02055779
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  • 5
    Digitale Medien
    Digitale Medien
    The digestion ofSaccharomyces cerevisiae byAcanthamoeba castellanii (1979)
    Springer
    Protoplasma 98 (1979), S. 63-71 
    Details
    ISSN: 1615-6102
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The digestion ofSaccharomyces cerevisiae byAcanthamoeba castellanii, at different times after feeding, has been examined by cytochemical techniques at electron microscope level and by measurement of yeast viability. The measurement of viability, combined with cytochemistry is presented as a novel method of examining the progress of digestion. Particular attention has been given to the temporal development of digestion. Vacuoles, probably primary lysosomes, have been identified containing acid phosphatase activity within minutes of feeding and these accumulate around and fuse with phagocytic vacuoles. Acid phosphatase levels in the digestive vacuoles appeared highest at 20 to 40 minutes. Yeast digestion was observed and yeast viability began to decline at this time. Mixing of autophagic and heterophagic material was also observed. At least half of the yeast population was still viable after 90 minutes. Our method (p-nitrophenyl phosphate) of enzyme localization has demonstrated plasma membrane associated acid phosphatase activity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01676662
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  • 6
    Digitale Medien
    Digitale Medien
    The fine structural localization of acid phosphatase in pore cells of embryonic and newly hatched Deroceras reticulatum (Pulmonata: Stylommatophora) (1979)
    Springer
    Cell & tissue research 204 (1979), S. 253-265 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Pore cells ; Fine structure ; Acid phosphatase ; Cell lysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The fine structure of the pore cells in pre- and post-hatched Deroceras reticulatum is described. The cells have been divided into three main types on morphological grounds, one type being particularly rich in glycogen. Certain pore cells contain haemocyanin granules in grooves below cytoplasmic tongues, and in characteristic double-membrane-bounded vesicles within dilated cisternae of rough endoplasmic reticulum, as well as in other identified areas. All types of pore cells show fine fibres reminiscent of collagen associated with the basal lamina and pore complexes. In addition to acid phosphatase activity in lysosomes and Golgi elements, intra- and extracisternal activity has been demonstrated in association with the rough endoplasmic reticulum. The intracisternal activity is in close proximity to the Golgi apparatus and may represent enzyme that is about to enter the GERL system. Extracisternal activity may be associated with cellular lysis and death, or may represent local areas of degradation leading to cytodifferentiation. Remnants of lysed pore cells appear to be taken up by connective tissue amoebocytes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234637
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  • 7
    Digitale Medien
    Digitale Medien
    Studies on transmembrane and paracellular phenomena in the foot of the slug Agriolimax reticulatus (Mü) (1977)
    Springer
    Cell & tissue research 183 (1977), S. 143-152 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Foot of Agriolimax reticulatus ; Paracellular uptake ; Peroxidase, lanthanum ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Using the enzyme peroxidase and ionic lanthanum as tracers, paracellular uptake has been demonstrated in the foot of the slug Agriolimax reticulatus (Mü). Both tracers appeared to pass between adjacent foot epithelial cells and were demonstrated in the zonula adhaerens, the septate desmosomes, and the intercellular spaces which occur beneath the septate junctions. Ferritin, a somewhat larger tracer, was excluded from all these sites. Ionic lanthanum was not normally pinocytosed in short incubation times. The epithelial cells could be induced to endocytose this marker, however, when combined with a variety of proteins. The implications these findings have on the uptake of molluscicides is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219998
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  • 8
    Digitale Medien
    Digitale Medien
    Endocytosis and aspects of autophagy in the foot epithelium of the slug Agriolimax reticulatus (Müller) (1977)
    Springer
    Cell & tissue research 181 (1977), S. 129-141 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Endocytosis ; Autophagy ; Foot-epithelium ; Mollusc (Agriolimax reticulatus)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The foot epithelium of the slug Agriolimax reticulatus (M) can function as a digestive epithelium and possesses a vacuolar system in which heterophagic and autophagic material is hydrolysed. Using ferritin and peroxidase as markers, the process of endocytosis has been demonstrated at the level of the electron microscope. The mechanisms involved with the uptake of each marker differed in that ferritin was confined to fairly large vacuoles, while peroxidase was present in smaller pinocytotic vesicles which ultimately fused to form larger vacuoles or multivesicular bodies. Cytochemical tests for acid phosphatase revealed that the latter bodies acquired hydrolytic enzyme to become secondary lysosomes. Acid phosphatase was also localized in the Golgi apparatus of the epithelial cells. In addition to the endocytotic activity, evidence for autophagy was found in the epithelial cells and this process was apparently enhanced during starvation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00222779
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  • 9
    Digitale Medien
    Digitale Medien
    A methacrylate embedding technique for combined autoradiography and acid phosphatase histochemistry (1985)
    Springer
    Journal of molecular histology 17 (1985), S. 467-475 
    Details
    ISSN: 1573-6865
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A method is described that enables the simultaneous application of autoradiography and histochemistry in tissue sections prepared using a hydroxyethyl methacrylate (HEMA) embedding medium. A novel fixation regime, using a 1∶9 v/v mixture of acetone and 10% neutral buffered formalin, improves section quality, histological staining and reduces tissue and cell shrinkage. The combined localization of [6-3H] thymidine incorporation and acid phosphatase in mouse thymus, duodenum, human stomach biopsy, earthworm and Walker tumour is described and counts of macrophages, phagocytosed cells, pyknotic cells, mitotic figures and thymidine-incorporating cells from young and old mouse thymus are presented.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01003206
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  • 10
    Digitale Medien
    Digitale Medien
    Cell autolysis and deletion in the planarian polycelis tenuis Iijima (1974)
    Springer
    Cell & tissue research 154 (1974), S. 265-274 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Cell autolysis ; Deletion ; Planaria ; Acid phosphatase ; Fine structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Selective cell autolysis and deletion is described in the normal adult planarian. This appears to be a common feature and the sequence of events leading from cytoplasmic vesiculation and peripheral lysis to complete cellular breakdown is described. — In lysing cells acid phosphatase activity can be demonstrated in the cytoplasm as well as in lysosome like vacuoles and occasionally in the Golgi apparatus. The role of cell autolysis and deletion in tissue regulation is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00223168
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