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  • 1
    Electronic Resource
    Electronic Resource
    Oxalic acid metabolism and calcium oxalate formation in Lemna minor L. (1987)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 10 (1987), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Axenic Lemna minor plants, which form numerous calcium oxalate crystals, were exposed to [14C]-glycolic acid, -glyoxylic acid, -oxalic acid and -ascorbic acid and prepared for microautoradiography by a technique that preserves only insoluble label to determine specifically the pathway leading to oxalic acid used for crystal formation. Label from glycolic, glyoxylic, and oxalic acids was incorporated into crystals. Label from oxalic acid was also found in starch when exposure to label was done in the light but not dark, while plastids specialized for lipid storage were heavily labelled under both conditions. Incorporation of label from glycolic and glyoxylic acids, but not oxalic acid, was inhibited in the presence of the glycolate oxidase inhibitors, αHPMS (2-pyridylhydroxy methanesulphonic acid) and mHBA (methyl 2-hydroxy-3-butynoic acid), and inhibition of labelling was not due to an effect on uptake. These studies show that the glycolate oxidase pathway to oxalic acid is operational in L. minor and that the product is available for crystal formation. Dark-grown plants form almost four times as many crystal cells (idioblasts) as do light-grown plants, indicating crystal formation is not in response to photorespiratory glycolate production. Label from [1-14C]ascorbic acid was also incorporated into crystals and labelling was inhibited by mHBA, indicating glycolic acid and/or glyoxylic acid are possible intermediates of ascorbic acid catabolism.The effect of nitrogen source on crystal formation was also investigated. Significantly more crystal idioblasts were formed, on a surface area basis, by plants grown on ammonium than by plants grown on nitrate nitrogen. When grown with mixed ammonium and nitrate, an intermediate number of crystal idioblasts were formed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/1365-3040.ep11603639
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  • 2
    Electronic Resource
    Electronic Resource
    Immunochemical studies on the role of the Golgi complex in protein-body formation in rice seeds (1986)
    Springer
    Planta 169 (1986), S. 471-480 
    Details
    ISSN: 1432-2048
    Keywords: Endosperm ; Golgi apparatus ; Oryza (protein bodies) ; Protein deposition ; Storage protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Antibodies raised against purified glutelins and prolamines were employed as probes to study the cellular routes by which these proteins are deposited into protein bodies of rice (Oryza sativa L.) endosperm. Three morphologically distinct protein bodies, large spherical, small spherical, and irregularly-shaped, were observed, in agreement with existing reports. Immunocytochemical studies showed the presence of glutelins in the irregularly-shaped protein bodies while the prolamines were found in both the large and small spherical protein bodies. Both the large and small spherical protein bodies, distinguishable by electron density and gold-labeling patterns, appear to be formed by direct deposition of the newly formed proteins into the lumen of the rough endoplasmic reticulum (ER). In contrast, glutelin protein bodies are formed via the Golgi apparatus. Small electron-lucent vesicles are often found at one side of the Golgi. Electron-dense vesicles, whose contents are labeled by glutelin antibody-gold particles, are commonly observed at the distal side of the Golgi apparatus and fuse to form the irregularly shaped protein bodies in endosperm cells. These observations indicate that the transport of rice glutelins from their site of synthesis, the ER, to the site of deposition, the protein bodies, is mediated by the Golgi apparatus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392095
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  • 3
    Electronic Resource
    Electronic Resource
    Characean charasome-complex and plasmalemma vesicle development (1981)
    Springer
    Protoplasma 107 (1981), S. 255-267 
    Details
    ISSN: 1615-6102
    Keywords: Chara ; Charasome development ; Coated membrane vesicles ; Endocytosis ; Nitella ; Plasmalemma invaginations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We report on an unusual phenomenon which occurs in some characean algae as a normal plasma membrane activity and also in association with charasome formation. The phenomenon of formation of coated invaginations of the plasma membrane was observed in twoChara and 6Nitella species. These invaginations are coated on their cytoplasmic surface, are 50–60 nm in diameter and rarely exceed 60 nm in length. They are abundant in the young cells ofChara andNitella and also occur in mature cells, but at a lower frequency.N. translucent is an exception in that coated invaginations were few in the young cells and absent in mature cells. Coated vesicles (50–60 nm diameter) were closely associated with these invaginations. Our observations suggest the vesicles may be derived from the invaginations by endocytosis. A close relationship was noted between the development of charasomes (plasmalemma modifications) and coated invaginations. Numerous coated invaginations are seen along the membranes of young charasomes; these invaginations appear to be associated with growth of the charasomes. Coated vesicles were not associated with the coated invaginations of the charasome membrane. The tubular network of cytoplasm and wall space seen in the mature charasome may be formed by fusion of coated invaginations of the developing charasomes, leaving cytoplasmic strands between the fused portions. Coated invaginations were not present along charasomes of the mature cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01276829
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  • 4
    Electronic Resource
    Electronic Resource
    The charasome periplasmic space (1981)
    Springer
    Protoplasma 107 (1981), S. 269-284 
    Details
    ISSN: 1615-6102
    Keywords: Chara ; Charasome-complex ; Freeze-fracture ; Negative staining ; Periplasmic space ; Tannic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Charasome structure, with special attention to the periplasmic space, is examined using various techniques. The periplasmic space appears electron lucent in sections stained with 2% aqueous uranyl acetate and lead citrate. When sections are stained with saturated methanolic uranyl acetate a densely staining central core can be seen within the periplasmic space. The region surrounding the core does not stain. If tannic acid is added to the fixative and rinse solutions during preparation of the tissue for TEM, the entire periplasmic space becomes stained. This space appears to be filled with a fine granular material. Charasomes prepared in this way appear as negatives of those stained with uranyl acetate. The periplasmic space does not contain polysaccharides of the type havingvic-glycol groups, as indicated by lack of staining by the silver methenamine technique. Severe plasmolysis of cells by treatment with 350 mM mannitol prior to fixation resulted in disruption of charasomes, but did not cause collapse of the structure. The periplasmic space of freeze-fractured charasomes contains a distinct granular material, while negatively stained isolated charasomes retain their structural configuration, even after air drying. The results give us new insight into the nature of the periplasmic space and confirm our earlier description of the charasome structure. This information is used to construct a model which attempts to explain how a structure such as the charasome can be formed along the plasmalemma of a cell having a high internal hydrostatic pressure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01276830
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  • 5
    Electronic Resource
    Electronic Resource
    Preparation and properties of pollen sporoplasts (1987)
    Springer
    Protoplasma 141 (1987), S. 47-55 
    Details
    ISSN: 1615-6102
    Keywords: Lilium longiflorum ; 4-Methylmorpholine N-oxide ; Pollen exine ; Sporoplast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Methods for the removal of exine from mature, ungerminatedLilium longiflorum pollen and release of intact gametophytes (sporoplasts) have been developed. These methods rely on the low temperature solvolytic activity of 4-methylmorpholine N-oxide (MMNO), which allows partial or complete detachment of exine from intine during subsequent washing procedures. These methods are: aqueous MMNO combined with cyclohexylamine (method I), aqueous MMNO at alkaline pH (method II), and aqueous MMNO containing a high Ca2+ concentration with added cellulysin and macerase (method III). Sporoplasts produced by methods I and II are most frequently completely separated from exine and, as shown by histochemical tests, enveloped by the intine layer. Selected enzyme activities in method II sporoplasts are measurable but, as indicated by other tests, considerable damage to the plasma membrane accompanies this treatment. Sporoplasts produced by melhod III largely remain attached to their ruptured exine layer and retain substantial biological competence in terms of extractable enzyme activities, membrane integrity, and respiration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01276787
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  • 6
    Electronic Resource
    Electronic Resource
    Structure and possible function(s) of charasomes; complex plasmalemma-cell wall elaborations present in some characean species (1980)
    Springer
    Protoplasma 104 (1980), S. 253-271 
    Details
    ISSN: 1615-6102
    Keywords: Bicarbonate transport ; Chara ; Charasome-complex ; Nitella ; Plasmalemma invaginations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Charasomes, complex membrane structures, were found along the longitudinal walls of internodal and lateral branch cells ofChara corallina andC. braunii, but not along their transverse walls or in other cell types. Charasome-complexes were larger and more numerous in the lateral branch cells than in internodal cells. InC. corallina, a dioecious species, especially large elaboration of charasome material occurs in the lateral branch cells of the female plant, sometimes reaching a cross-sectional width which is as great as that of the adjacent cell wall. Chara internodes transport hydroxyl (OH−) out of the cell and bicarbonate (HCO3 −) into the cell. Spatial distribution of charasomes along the cell was examined with respect to these transport phenomena, which occur at specific identifiable regions along the cell. Charasome-complexes were always found in regions in which HCO3 − transport occurs but were often fewer, reduced in size or absent in areas of OH− efflux.Nitella flexilis exhibited similar patterns of OH− and HCO3 − transport along the cell; however, there was a complete absence of charasomes. Ultrastructural examinations onNitella translucens indicated that charasomes were also absent in this species. The observation that charasomes are present in both transport regions ofChara but are totally lacking in the twoNitella spp. indicates that the charasome-complex is not involved in transport of either substance. Other possible functions for the charasomes, including a role in osmoregulation, are discussed. Charasome substructure is the same in bothChara species, consisting of a mass of short (50 nm average length) anastomosing tubules (30 nm average diameter) derived from the plasmalemma. The interior of the tubules is open to the cytoplasm while the area surrounding the tubules is ultimately open to the wall and thus can be considered to be wall space. Charasomes are quite variable in size and shape, but are roughly globular, with the bulk of the structure projecting into the cell cytoplasm. Tubular components of the charasome were sometimes seen to extend into the microfibrillar wall matrix. A three dimensional model of the charasome-complex presented details the great complexity of this membrane system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279771
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  • 7
    Electronic Resource
    Electronic Resource
    Spatial and temporal expression of sucrose transport-related genes in developing cotyledons ofVicia faba L. (1997)
    Springer
    Protoplasma 200 (1997), S. 35-50 
    Details
    ISSN: 1615-6102
    Keywords: Developmental gene expression ; H+/sucrose symporter ; P-type H+-ATPase ; Sucrose-binding protein ; Transfer cells ; Vicia faba ; Cotyledons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Dry-matter accumulation by developing cotyledons of grain legumes includes a mandatory influx of photoassimilates, largely in the form of sucrose, from the seed apoplasm across the plasma membranes of the cotyledon cells. This study examined the temporal and spatial expression of an H+/sucrose symporter, a P-type H+-ATPase, and a sucrose-binding protein (SBP) in cotyledons ofVicia faba L. throughout their development. The flux of dry matter and sucrose symporter activity exhibited identical temporal trends. These were a marked increase during cotyledon expansion to a plateau maintained until cotyledon maturity. Thereafter both parameters declined precipitously. The temporal changes in sucrose symporter activity were accounted for by shifts in its Vmax. Transcript levels of the H+/sucrose symporter followed a similar temporal pattern to the sucrose symporter activity suggesting regulation by gene expression. Equivalent conclusions were drawn for SBP and the H+-ATPase expression during cotyledon expansion. Thereafter, during seed filling, the transcript levels of SBP and H+-ATPase did not closely follow that found for the sucrose symporter. A progressive wave of gene expression in the abaxial epidermal cells spread from the cotyledon region juxtaposed to the non-vascular region of the seed coat at the pole distal from the funicle. The pattern of expression progressed most rapidly along the median longitudinal plane of the cotyledons and more slowly outward to their margins. The densities of SBP and H+-ATPase, inserted into the plasma membranes of the abaxial epidermal cells, increased throughout cotyledon expansion. Gene expression (sucrose symporter) and membrane insertion of the gene products (SBP, H+-ATPase) were closely associated with the initiation and development of wall ingrowths in the abaxial epidermal cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01280733
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  • 8
    Electronic Resource
    Electronic Resource
    Cell and calcium oxalate crystal growth is coordinated to achieve high-capacity calcium regulation in plants (2000)
    Springer
    Protoplasma 214 (2000), S. 166-179 
    Details
    ISSN: 1615-6102
    Keywords: Biomineralization ; Calcium ; Calcium oxalate ; Crystal ; Cytoskeleton ; Pistia stratiotes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Crystal idioblasts are cells which are specialized for accumulation of Ca2+ as a physiologically inactive, crystalline salt of oxalic acid. Using microautoradiographic, immunological, and ultrastructural techniques, the process of raphide crystal growth, and how crystal growth is coordinated with cell growth, was studied in idioblasts ofPistia stratiotes. Incorporation of45Ca2+ directly demonstrated that, relative to surrounding mesophyll cells, crystal idioblasts act as high-capacity Ca2+ sinks, accumulating large amounts of Ca2+ within the vacuole as crystals. The pattern of addition of Ca2+ during crystal growth indicates a highly regulated process with bidirectional crystal growth. In very young idioblasts,45Ca2+ is incorporated along the entire length of the needle-shaped raphide crystals, but as they mature incorporation only occurs at crystal tips in a bidirectional mode. At full maturity, the idioblast stops Ca2+ uptake, although the cells are still alive, demonstrating an ability to strictly regulate Ca transport processes at the plasma membrane. In situ hybridization for ribosomal RNA shows young idioblasts are extremely active cells, are more active than older idioblasts, and have higher general activity than surrounding mesophyll cells. Polarizing and scanning electron microscopy demonstrate that the crystal morphology changes as crystals develop and includes morphological polarity and an apparent nucleation point from which crystals grow bidirectionally. These results indicate a carefully regulated process of biomineralization in the vacuole. Finally, we show that the cytoskeleton is important in controlling the idioblast cell shape, but the regulation of crystal growth and morphology is under a different control mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279061
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  • 9
    Electronic Resource
    Electronic Resource
    Incorporation of strontium into plant calcium oxalate crystals (1986)
    Springer
    Protoplasma 130 (1986), S. 199-205 
    Details
    ISSN: 1615-6102
    Keywords: Calcium ; Crystals ; Energy dispersive X-ray analysis ; Lemna minor ; Oxalate ; Strontium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Lemna minor, which produces many calcium oxalate raphide crystals, was grown on media containing in addition to Ca, 200 μM of one of the following divalent cations: Ba, Cd, Co, Mn or Sr. Energy dispersive X-ray analysis showed that only Sr was incorporated into the raphides at levels detectable by the analysis technique. Incorporation of Sr into other insoluble compounds, such as cell wall material, could not be detected. Plant species which form different crystal types in their leaves (Beta vulgaris, crystal sand;Arthrostema ciliatum, druse;Glycine canescens, prismatic) also incorporated Sr into their crystals when grown hydroponically on nutrient medium containing 200 μM Sr. Axenic cultures ofL. minor were used to examine further the process of Sr incorporation into plant crystals. When grown on nutrient solution with 5 μM Ca, increasing the Sr concentration resulted in increases of the amount of Sr incorporated into the raphide crystals. The ratio of Sr to Ca became greater as the Sr concentration was increased. This ratio change was due to both an increase in the amount of Sr incorporated and a decrease in the Ca incorporated. Analysis of the number of crystal idioblasts formed as a function of Sr concentration shows fewer idioblasts are produced as Sr became high. Competition with Ca and interference of Ca utilization by Sr is indicated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01276601
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  • 10
    Electronic Resource
    Electronic Resource
    Developmental features of calcium oxalate crystal sand deposition inBeta vulgaris L. Leaves (1984)
    Springer
    Protoplasma 120 (1984), S. 216-223 
    Details
    ISSN: 1615-6102
    Keywords: Beta vulgaris ; Calcium oxalate ; Crystals ; de novo membrane synthesis ; Vacuole
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sugar beet (Beta vulgaris L.) leaf has a layer of cells extended laterally between the palisade parenchyma and spongy mesophyll that develop numerous small crystals (crystal sand) within their vacuoles. Solubility studies and histochemical staining indicate the crystals are calcium oxalate. The crystals are deposited within the vacuoles early during leaf development, and at maturity the cells are roughly spherical in shape and 2 to 3 times larger than other mesophyll cells. Crystal deposition is preceeded by formation of membrane vesicles within the vacuole. The membranes are synthesizedde novo in the vacuole and have a typical trilaminate structure as viewed with the TEM. The membranes are formed within paracrystalline aggregates of tubular particles (6–8nm outer diameter) as membrane sheets, but are later organized into chambers or vesicles. Calcium oxalate is then precipitated within the membrane chambers. The tubular particles involved in membrane synthesis are usually present in the vacuoles of mature crystal cells, but in very small amounts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01282602
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