Library

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
    An environment for three-dimensional shaded perspective display of cell components
    Amsterdam : Elsevier
    Micron And Microscopica Acta 17 (1986), S. 349-357 
    Details
    ISSN: 0739-6260
    Keywords: Three-dimensional reconstruction ; cell ultrastructure ; computer display environment ; dictyosomes ; electron micrograph series ; image processing ; shading program ; smoothing program
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Electrical Engineering, Measurement and Control Technology , Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0739-6260(86)90027-4
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Lipid metabolism during germination of tobacco pollen
    Amsterdam : Elsevier
    Phytochemistry 27 (1988), S. 2027-2031 
    Details
    ISSN: 0031-9422
    Keywords: Nicotiana sylvestris ; Solanaceae ; acetate incorporation ; lipid composition ; phosphate incorporation. ; pollen germination
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0031-9422(88)80090-6
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Granulocrine Ausscheidung von Narbensekret durch Vesikel des Endoplasmatischen Retikulums beiAptenia cordifolia (1977)
    Springer
    Protoplasma 92 (1977), S. 243-251 
    Details
    ISSN: 1615-6102
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die jungen Narbenpapillen vonAptenia cordifolia scheiden während der Blühzeit ein polysaccharid- und proteinhaltiges Sekret aus. Die Feinstruktur zeigt u. a. Chloroplasten vermutlich während der Metamorphose zu Chromoplasten und als auffälligste Komponente zahlreiche 0,5–1,5 μm große, z. T. miteinander verschmolzene Sekretvesikel mit fibrillärem Inhalt. Einige dieser Vesikel stehen mit der intrazisternalen Phase des ER in direkter Verbindung, andere fusionieren mit dem Plasmalemma. Der Golgi-Apparat ist nur schwach entwickelt und weist keine hypersekretorische Aktivität auf. Auf Grund dieser Befunde wird angenommen, daß der Sekrettransport und die exocytotische Ausschleusung des Sekrets durch ER-Vesikel erfolgen.
    Notes: Summary During anthesis the young stigma papillae ofAptenia cordifolia produce a slime containing polysaccharides and proteins. Among other details of the ultrastructure there are chloroplasts during their transformation into chromoplasts, and, as the most conspicuous item, numerous vesicles with fibrillar contents, measuring 0,5–1,5 μm in diameter, partly fused with each other. Some vesicles are directly connected with the intracisternal space of the ER, other vesicles are merged with the plasmalemma. The Golgi apparatus is developed but weakly, and shows no hypersecretory activity. Because of these observations a transport and an exocytotic extrusion of the secretion substances via ER vesicles is concluded.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279461
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Plasmatubules in the pollen tubes of Nicotiana sylvestris (1988)
    Springer
    Planta 173 (1988), S. 35-41 
    Details
    ISSN: 1432-2048
    Keywords: Membrane extension ; Nicotiana (plasmatubules) ; Nutrient uptake (pollen tube) ; Plasma membrane ; Plasmatubule ; Pollen tube
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ultrastructural studies of the pollen tubes of Nicotiana sylvestris grown in the pistil revealed an extensive development of plasmatubules formed by evaginations of the plasma membrane. The plasmatubules occurred as twisted tubular structures in the periplasmic space along the tube wall and, in cross section, exhibited circular profiles with an outer diameter of 28±4 nm. They were also seen in deep, pocket-like invaginations of the plasma membrane and in this case the profiles had an outer diameter of 34±8 nm. In the pocket-like invaginations they were partially branched and often closely packed to form groups with obvious patterns. The enlargement of the plasma-membrane area resulting from plasmatubules formed along the tube wall was about six-to tenfold. Pollen tubes grown in vitro exhibited poorly developed plasmatubules. It is suggested that the large extension of the plasma membrane could enhance the uptake of nutrients, and thus might be responsible for the comparatively fast growth of pollen tubes in the pistil. Moreover, it is also assumed that the turnover rate of the Golgi apparatus must be higher in pollen tubes growing in vivo than in vitro, in order to provide a sufficient amount of membrane for the formation of the plasma membrane with its tubular modifications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00394484
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Ultrastructure and a possible function of the intercisternal elements in dictyosomes (1978)
    Springer
    Planta 138 (1978), S. 29-33 
    Details
    ISSN: 1432-2048
    Keywords: Dictyosomes ; Golgi apparatus ; Intercisternal elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The slime-producing dictyosomes in the placentary papillae of Aptenia cordifolia (L.f.) Schwant. show some structural peculiarities: (1) the number of their cisternae is conspicuously large in comparison with those of other cormophyta; (2) the spaces between the extremely flat vesicle-producing cisternae of the maturing face are considerably higher than those between the other cisternae; (3) the intercisternal elements show a pearl-string form rather than a fibrillar form-especially on tangential sections. Based on personal and on cited findings, the following hypothesis is developed: The intercisternal elements effect the compression of the central region of the secretory cisternae. This causes the production of vesicles to remain restricted to the marginal region of the cisternae, even if these cisternae contain hypertonic or soaking substances.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392910
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Auffällige ER-Konfigurationen in Protein-Polysaccharidschleim-sezernierenden pflanzlichen Drüsen (1977)
    Springer
    Planta 133 (1977), S. 161-167 
    Details
    ISSN: 1432-2048
    Keywords: Ovary glands ; Slime secretion ; Unusual ER-configurations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the ovary of Aptenia cordifolia and Platythyra haeckeliana placentary papillae produce a slime containing polysaccharides and proteins. These papillae show two types of conspicuous vacuoles enclosed by rough ER cisternae and complexes of concentrically arranged rough ER. The enclosed vacuoles probably play an important role in the accumulation of the polysaccharide-protein slime. In the case of storage vesicles (first vacuole type) derivates of the Golgi apparatus are enclosed by ER. In other instances (second vacuole type) ER cisternae which have lost their membrane-bound ribosomes seem to delimit protoplasmic regions free of organelles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00391915
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    In vitro cytotoxicity testing for prediction of acute human toxicity (1994)
    Springer
    Cell biology and toxicology 10 (1994), S. 155-162 
    Details
    ISSN: 1573-6822
    Keywords: in vitro cytotoxicity ; cell culture ; protein synthesis ; proline incorporation ; radiolabeling ; cellular protein ; pollen tube growth inhibition ; MEIC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract This study was designed to compare the cytotoxic concentrations of chemicals, determined with three independentin vitro cytotoxicity testing protocols, with each other and with established animal LD50 values, and against human toxic concentrations for the same chemicals. Ultimately, these comparisons allow us to evaluate the potential ofin vitro cell culture methods for the ability to screen a variety of chemicals for prediction of human toxicity. Each laboratory independently tested 50 chemicals with known human lethal plasma concentrations and LD50 values. Two of the methods used monolayer cell cultures to measure the incorporation of radiolabeled amino acids into newly synthesized proteins and cellular protein content, while the third technique used the pollen tube growth test. The latter is based on the photometric quantification of pollen tube mass production in suspension culture. Experiments were performed in the absence or presence of increasing doses of the test chemical, during an 18- to 24-h incubation. Inhibitory concentrations were extrapolated from concentration-effect curves after linear regression analysis. Comparison of the cytotoxic concentrations confirms previous independent findings that the experimental IC50 values are more accurate predictors of human toxicity than equivalent toxic blood concentrations (HETC values) derived from rodent LD50s. In addition, there were no conclusive statistical differences among the methods. It is anticipated that, together, these procedures can be used as a battery of tests to supplement or replace currently used animal protocols for human risk assessment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00757558
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    The influence of chlorsulfuron and metsulfuron methyl on root growth and on the ultrastructure of root tips of germinating maize seeds (1996)
    Springer
    Plant and soil 180 (1996), S. 19-28 
    Details
    ISSN: 1573-5036
    Keywords: herbicides ; chlorsulfuron ; metsulfuron methyl ; root tip ultrastructure ; root growth ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Seeds of Zea mays L., germinating in soil, were exposed to very low doses of the sulfonylurea herbicides chlorsulfuron and metsulfuron methyl. At a concentration of 0.012 mg L−1, chlorsulfuron caused 72% and metsulfuron methyl 55% growth reduction of the young primary roots. Both herbicides also caused obvious injuries to the root tips. Scanning electron microscopic observations of the root tip surfaces indicated an inhibition of slime secretion at a herbicide concentration of 1.5 mg L−1. Transmission electron microscopy revealed obvious changes to the nuclei and deformation of radial cell walls in the primary root cortex at 0.012 and 1.5 mg L−1 for both herbicides. Moreover, the secretory cells of the root cap periphery showed partially irregular deposition of premature cell wall or slime material at a concentration of 0.012 mg L−1 of both herbicides. From the results of our electron microscopic observations we conclude that the primary roots of maize seedlings are seriously affected by extremely low concentrations of even those herbicides which (as chlorsulfuron and metsulfuron methyl) have been developed to inhibit the growth of dicotyledonous weeds. Moreover, we suggest that the frequently observed growth retardation of crop seedlings is a consequence of early root tip injuries caused by herbicide residues in the soil. ei]H Lambers
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00015407
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Ultrastructural responses of root caps to the herbicides chlorsulfuron and metsulfuron methyl (1994)
    Springer
    Plant and soil 167 (1994), S. 127-134 
    Details
    ISSN: 1573-5036
    Keywords: herbicides ; chlorsulfuron ; metsulfuron methyl ; root cap ultrastructure ; root growth ; Pisum sativum ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Herbicide residues may affect seedlings during early stages of their development. We studied this possibility by the use of light and electron microscopy after incubation of germinating seeds ofPisum sativum L. andZea mays L. with different concentrations of chlorsulfuron and metsulfuron-methyl. By in vitro experiments, we have shown that both herbicides caused growth reduction of the very young roots, and severe ultrastructural alterations and injuries of the root caps of both species. Chlorsulfuron caused increase of electron-dense material in the vacuoles, cytoplasmic degeneration even in the inner secretory cell layers of the cap, and disruption of the amyloplast envelopes with release of the statolithic starch grains. In the initial cell complex of the root cap, the herbicides caused the formation of large concentric aggregates of the rough ER and wall disformations in the cells adjacent to this complex. Scanning electron microscopic observations revealed a decrease of the slime layer ensheathing the root cap and the subapical root surface. We conclude that even in early stages of seed germination, both herbicides seriously affect the gravity perception centre (consisting of the statocytes), and the secretory tissue of the root caps, thus probably disturbing the processes of gravitropism and the protective slime secretion of the roots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01587607
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Membrane flow in plants: Fractionation of growing pollen tubes of tobacco by preparative free-flow electrophoresis and kinetics of labeling of endoplasmic reticulum and golgi apparatus with [3H]leucine (1986)
    Springer
    Protoplasma 132 (1986), S. 38-50 
    Details
    ISSN: 1615-6102
    Keywords: Pollen tube ; Endoplasmic reticulum ; Golgi apparatus ; Membrane biogenesis ; Plasma membrane (Tobacco)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Tobacco (Nicotiana tabacum L.) pollen, germinated 4 hours in suspension culture, was labeled with radioactive leucine and fractionated into constituent membranes by the technique of preparative free-flow electrophoresis. Tubes were ruptured by sonication directly into the electrophoresis buffer. Unfortunately, the Golgi apparatus of the rapidly elongating pollen tubes did not survive the sonication step. However, it was possible to obtain useful fractions of endoplasmic reticulum and mitochondria. To obtain Golgi apparatus, glutaraldehyde was added to the homogenization buffer during sonication. Plasma membrane, which accounted for only about 3% of the total membrane of the homogenates as determined by staining with phosphotungstate at low pH, was obtained in insufficient quantity and fraction purity to permit analysis. Results show rapid incorporation of [3H]leucine into endoplasmic reticulum followed by rapid chase out. The half-time for loss of radioactivity from the pollen tube endoplasmic reticulum was about 10 minutes. Concomitant with the loss of radioactivity from endoplasmic reticulum, the Golgi apparatus fraction was labeled reaching a maximum 20 minutes post chase. The findings suggest flow of membranes from endoplasmic reticulum to the Golgi apparatus during pollen tube growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01275788
    Library Location Call Number Volume/Issue/Year 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...