ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    A novel callose synthase from pollen tubes of Nicotiana (1993)
    Springer
    Planta 191 (1993), S. 470-481 
    Details
    ISSN: 1432-2048
    Keywords: Callose ; Callose synthase ; Nicotiana ; Pollen tube ; Protease activation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pollen-tube cell walls are unusual in that they are composed almost entirely of callose, a (1,3)-β-linked glucan with a few 6-linked branches. Regulation of callose synthesis in pollen tubes is under developmental control, and this contrasts with the deposition of callose in the walls of somatic plant cells which generally occurs only in response to wounding or stress. The callose synthase (uridine-diphosphate glucose: 1,3-β-d-glucan 3-β-d-glucosyl transferase, EC 2.4.1.34) activities of membrane preparations from cultured pollen tubes and suspension-cultured cells of Nicotiana alata Link et Otto (ornamental tobacco) exhibited different kinetic and regulatory properties. Callose synthesis by membrane preparations from pollen tubes was not stimulated by Ca2+ or other divalent cations, and exhibited Michaelis-Menten kinetics only between 0.25 mM and 6 mM uridine-diphosphate glucose (K m 1.5–2.5 mM); it was activated by β-glucosides and compatible detergents. In contrast, callose synthesis by membrane preparations from suspension-cultured cells was dependent on Ca2+, and in the presence of 2 mM Ca2+ exhibited Michaelis-Menten kinetics above 0.1 mM uridine-diphosphate glucose (K m 0.45 mM); it also required a β-glucoside and low levels of compatible detergent for full activity, but was rapidly inactivated at higher levels of detergent. Callose synthase activity in pollen-tube membranes increased ten fold after treatment of the membranes with trypsin in the presence of detergent, with no changes in cofactor requirements. No increase in callose synthase activity, however, was observed when membranes from suspension-cultured cells were treated with trypsin. The insoluble polymeric product of the pollen-tube enzyme was characterised as a linear (1,3)-β-d-glucan with no 6-linked glucosyl branches, and the same product was synthesised irrespective of the assay conditions employed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195748
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Histochemistry and composition of the cell walls of styles of Nicotiana alata Link et Otto (1994)
    Springer
    Planta 195 (1994), S. 217-225 
    Details
    ISSN: 1432-2048
    Keywords: Arabinogalactan protein ; Cell wall ; Lignin ; Nicotiana ; Polysaccharide ; Style
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cell walls of styles of Nicotiana alata Link et Otto (ornamental tobacco; Solanaceae) were analysed chemically and examined histochemically. Cell-wall preparations were obtained from whole styles and from isolated transmitting-tissue cells. The style epidermal cells were shown histochemically to have thick, lignified secondary walls. These walls probably constituted a large proportion of the cell-wall preparation from whole styles as analysis of whole-style walls indicated that the major polysaccharides were xylans and cellulose, which are typical of lignified secondary walls of Magnoliopsida (dicotyledons). Lignification of the style epidermal walls was also demonstrated histochemically in 10 other species (5 genera including Nicotiana) of the sub-family Cestroideae of the Solanaceae, but not in 15 species (9 genera) of the sub-family Solanoideae of the Solanaceae, nor in 3 other species of dicotyledons and 2 species of Liliopsida (monocotyledons). Analysis of the cell-wall preparation from isolated transmitting-tissue cells of N. alata indicated that these contained cellulose, xyloglucans, and pectic polysaccharides, which is typical of primary cell walls of dicotyledons. However, the analysis indicated that the walls also contained an unusually high proportion of Type II arabinogalactans. Staining of the transmitting-tissue cell-wall preparation with β-glucosyl Yariv reagent, a histochemical reagent specific for arabinogalactan proteins, confirmed their presence, which may be related to the role of these cells in secreting the stylar extracellular matrix.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00199682
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Characterisation of extracellular polysaccharides from suspension cultures of members of the Poaceae (2000)
    Springer
    Planta 210 (2000), S. 261-268 
    Details
    ISSN: 1432-2048
    Keywords: Key words: Cell-suspension culture – Compositional analysis – Differentiation – Extracellular polysaccharide – Poaceae – Root mucilage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. Microscopic examination of suspension- cultured cells of Phleum pratense L., Panicum miliaceum L., Phalarisaquatica L. and Oryza sativa L. showed that they were comprised of numerous root primordia. Polysaccharides secreted by these suspension cultures contained glycosyl linkages consistent with the presence of high proportions of root mucilage-like polysaccharides. In contrast, suspension-cultured cells of Hordeum vulgare L. contained mostly undifferentiated cells more typical of plant cells in suspension culture. The polysaccharides secreted by H. vulgare cultures contained mostly linkages consistent with the presence of glucuronoarabinoxylan. The soluble polymers secreted by cell-suspension cultures of Phleum pratense contained 70% carbohydrate, 14% protein and 6% inorganic material. The extracellular polysaccharides were separated into four fractions by anion-exchange chromatography using a gradient of imidazole-HCl at pH 7.0. From glycosyl-linkage analyses, five polysaccharides were identified: an arabinosylated xyloglucan (comprising 20% of the total polysaccharide), a glucomannan (6%), a type-II arabinogalactan (an arabinogalactan-protein; 7%), an acidic xylan (3%), and a root-slime-like polysaccharide, which contained features of type-II arabinogalactans and glucuronomannans (65%).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00008133
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Membrane fractionation and enrichment of callose synthase from pollen tubes of Nicotiana alata Link et Otto (1998)
    Springer
    Planta 205 (1998), S. 380-388 
    Details
    ISSN: 1432-2048
    Keywords: Key words: Callose ; Callose synthase ; Nicotiana ; Plasma membrane ; Pollen tube ; Product entrapment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. The callose synthase (UDP-glucose: 1,3-β-d-glucan 3-β-d-glucosyl transferase; EC 2.4.1.34) enzyme (CalS) from pollen tubes of Nicotiana alata Link et Otto is responsible for developmentally regulated deposition of the cell wall polysaccharide callose. Membrane preparations from N. alata pollen tubes grown in liquid culture were fractionated by density-gradient centrifugation. The CalS activity sedimented to the denser regions of the gradient, approximately 1.18 g · ml−1, away from markers for Golgi, endoplasmic reticulum and mitochondria, and into fractions enriched in ATPase activity and in membranes staining with phosphotungstic acid at low pH. This suggests that pollen-tube CalS is localised in the plasma membrane. Callose synthase activity from membranes enriched by downward centrifugation was solubilised with digitonin, which gave a 3- to 4-fold increase in enzyme activity, and the solubilised activity was then enriched a further 10-fold by product entrapment. The complete procedure gave final CalS specific activities up to 1000-fold higher than those of pollen-tube homogenates. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that several polypeptides co-fractionated with CalS activity through purification, with a polypeptide of 190 kDa being enriched in product-entrapment pellets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004250050334
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Role of a callose synthase zymogen in regulating wall deposition in pollen tubes of Nicotiana alata Link et Otto (1999)
    Springer
    Planta 208 (1999), S. 528-538 
    Details
    ISSN: 1432-2048
    Keywords: Key words: Callose ; Callose synthase ; Cell wall ; Nicotiana alata ; Pollen tube ; Zymogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. The callose synthase (CalS) activity of membrane preparations from cultured Nicotiana alata Link & Otto pollen tubes is increased several-fold by treatment with trypsin in the presence of digitonin, possibly due to activation of an inactive (zymogen) form of the enzyme. Active and inactive forms of CalS are also present in stylar-grown tubes. Callose deposition was first detected immediately after germination of pollen grains in liquid medium, at the rim of the germination aperture. During tube growth the 3-linked glucan backbone of callose was deposited at an increasing rate, reaching a maximum of 65 mg h−1 in tubes grown from 1 g pollen. Callose synthase activity was first detected immediately after germination, and then also increased substantially during tube growth. Trypsin caused activation of CalS throughout a 30-h time course of tube growth, but the degree of activation was higher for younger pollen tubes. Over a 10-fold range of callose deposition rates, the assayed CalS activity was sufficient to account for the rate of callose deposition without trypsin activation, implying that the form of CalS active in isolated membranes is responsible for callose deposition in intact pollen tubes. Sucrose-density-gradient centrifugation separated a lighter, intracellular membrane fraction containing only inactive CalS from a heavier, plasma-membrane fraction containing both active and inactive CalS, with younger pollen tubes containing relatively more of the inactive intracellular enzyme. The increasing rate of callose deposition during pollen-tube growth may thus be caused by the transport of inactive forms of CalS from intracellular membranes to the plasma membrane, followed by the regulated activation of these inactive forms in this final location.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004250050590
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Isolation and characterization of cell walls from the mesocarp of mature grape berries (Vitis vinifera) (1997)
    Springer
    Planta 203 (1997), S. 93-100 
    Details
    ISSN: 1432-2048
    Keywords: Key words: Berry (Cell wall ; grape) ; Cell wall (compositional analysis) ; Fruit (cell wall) ; Polysaccharide ; Vitis (berry ; cell wall)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. Cell walls have been isolated from the mesocarp of mature grape (Vitis vinifera L.) berries. Tissue homogenates were suspended in 80% (v/v) ethanol to minimise the loss of water-soluble wall components and wet-sieved on nylon mesh to remove cytoplasmic material. The cell wall fragments retained on the sieve were subsequently treated with buffered phenol at pH 7.0, to inactivate any wall-bound enzymes and to dislodge small amounts of cytoplasmic proteins that adhered to the walls. Finally, the wall preparation was washed with chloroform/methanol (1:1, v/v) to remove lipids and dried by solvent exchange. Scanning electron microscopy showed that the wall preparation was essentially free of vascular tissue and adventitious protein of cytoplasmic origin. Compositional analysis showed that the walls consisted of approximately 90% by weight of polysaccharide and less than 10% protein. The protein component of the walls was shown to be rich in arginine and hydroxyproline residues. Cellulose and polygalacturonans were the major constituents, and each accounted for 30–40% by weight of the polysaccharide component of the walls. Substantial varietal differences were observed in the relative abundance of these two polysaccharides. Xyloglucans constituted approximately 10% of the polysaccharide fraction and the remainder was made up of smaller amounts of mannans, heteroxylans, arabinans and galactans.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004250050169
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Stimulation of membrane-associated polysaccharide synthetases by a membrane potential in developing cotton fibers (1981)
    Springer
    Planta 152 (1981), S. 346-351 
    Details
    ISSN: 1432-2048
    Keywords: Cellulose synthetase ; β-1,3-Glucan synthetase ; Fibers ; Gossypium ; Membrane potential ; Polysaccharide synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Conditions which induce a transmembrane electrical potential, positive with respect to the inside of membrane vesicles, result in a substantial (4–12-fold) stimulation of the activity of membrane-associated β-glucan synthetases in a membrane preparation derived from the developing cotton (Gossypium hirsutum L.) fiber. Induction of electrical potentials which are negative with respect to the inside of the membrane vesicle results in little or no stimulation of β-glucan synthesis. Those products whose synthesis is stimulated are mainly β-1,3-glucan, but there is also a considerable increase in β-1,4-glucan. No α-1,4-glucan (starch) was detected in the reaction products. A transmembrane pH gradient was found to have no effect on β-glucan synthesis. The results indicate that a transmembrane electrical potential can influence, either directly or indirectly, the activity of membrane-associated polysaccharide synthetases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388260
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Localisation and expression of arabinogalactan-proteins in the ovaries of Nicotiana alata Link and Otto (1995)
    Springer
    Sexual plant reproduction 8 (1995), S. 278-282 
    Details
    ISSN: 1432-2145
    Keywords: Arabinogalactan-proteins ; Ovary ; Nicotiana ; Pollination ; Flower development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The transmitting-tissue cells of the style of flowering plants secrete a complex extracellular matrix through which pollen tubes grow to the ovary to effect fertilisation. This matrix is particularly rich in a class of proteoglycans, the arabinogalactan-proteins (AGPs). AGPs from the ovary of Nicotiana alata were found to be developmentally regulated, as the different charge classes of AGPs altered during floral development. The AGPs from the mature ovary had charge characteristics that were distinct from those previously reported for the stigma and style. However, the concentration of AGP (0.6 μg/ml fresh weight) in the ovary did not change during development, or in response to either compatible or incompatible pollination. The AGPs of the ovary are mainly associated with the epidermis of the placenta.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229384
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Pyruvated carrageenans from Solieria robusta and its adelphoparasite Tikvahiella candida (1999)
    Springer
    Hydrobiologia 398-399 (1999), S. 401-409 
    Details
    ISSN: 1573-5117
    Keywords: carrageenans ; chemotaxonomy ; Gigartinales ; Solieria robusta ; Solieriaceae ; structure determination ; Tikvahiella candida
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Solieria, the type genus of the commercially important red algal family Solieriaceae (Gigartinales), contains seven or eight species, three of which are represented in Australia. The cell-wall galactans of the most common Australian Solieria species, S. robusta (Greville) Kylin, were analysed by a combination of compositional assays, linkage analysis, and Fourier transform infrared (FTIR) and 13C nuclear magnetic resonance (NMR) spectroscopy. They are shown to be composed predominantly of carrabiose 2,4'-disulphate units (the repeating unit of ι-carrageenan) and a significant proportion of 4',6'-pyruvated carrabiose 2-sulphate units. The constituent sugars, pyruvate content, FTIR spectrum, and linkage and substitution patterns of the galactans from Tikvahiella candida Kraft et Gabrielson, an adelphoparasite of Solieria robusta, closely resemble those of its host and furnish evidence in support of a close phylogenetic relationship between the two species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017084627296
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Identification of truncated forms of lipophosphoglycan in mutant cloned lines ofLeishmania major that are deficient in mature lipophosphoglycan (1993)
    Springer
    Parasitology research 79 (1993), S. 435-438 
    Details
    ISSN: 1432-1955
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00931836
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...