ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • Articles  (8)
  • Cell & Developmental Biology  (4)
  • Plasma membrane  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Planta 141 (1978), S. 51-58 
    ISSN: 1432-2048
    Keywords: Cell wall ; Cellulose ; Freeze-etching ; Glaucocystis ; Microfibrils (cellulose) ; Morphogenesis ; Plasma membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Freeze-fracturing of Glaucocystis nostochinearum Itzigsohn cells during cell-wall microfibril deposition indicates that unidirectionally polarized microfibril ends are localized in a “zone of synthesis” covering about 30% of the sarface area of the plasma membrane. Within this zone there are about 6 microfibril ends/μm2 cell surface. It is proposed that microfibrils are generated by the passage of their tips over the cell surface and that the pattern of microfibril organization at the poles of the cells, in which microfibrils of alternate layers are interconnected at 3 “rotation centres”, results directly from the pattern of this translation of microfibril tips. In a model of the deposition pattern it is proposed that the zone of synthesis may split into 3 sub-zones as the poles are approached, each sub-zone being responsible for the generation of one rotation centre. It is demonstrated that the microfibrillar component of the entire wall could be generated by the steady translation of the microfibril tips (at which synthesis is presumed to occur) over the cell surface at a rate of 0.25–0.5 μm min-1. Microcinematography indicates that the protoplast rotates during cell-wall deposition, and it is proposed that this rotation may play a role in the generation of the microfibril deposition pattern.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1615-6102
    Keywords: Boergesenia forbesii ; Microfibrils ; Microtubules ; Plasma membrane ; Sectioned material ; Terminal complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Transmembrane linear terminal complexes considered to be involved in the synthesis of cellulose microfibrils have been described in the plasma membrane ofBoergesenia forbesii. Evidence for the existence of these structures has been obtained almost exlusively using the freeze etching technique. In the present study an attempt has been made to complete these studies using conventional fixation, staining, and sectioning procedures. In developing cells ofBoergesenia forbesii, strongly stained structures traversing the plasma membrane and averaging 598.9 nm ± 171.3 nm in length, 28.7 nm ± 4.2 nm in width, and 35.2 nm ± 6.6 nm in depth have been demonstrated. These structures are considered to be linear terminal complexes. At their distal (cell wall) surface, they appear to be closely associated with cellulose microfibrils. At the proximal (cytoplasmic) surface, they are associated with microtubules and polysomes. A model of the possible interrelation of the terminal complexes and microtubules leading to the generation of cell wall microfibrils is proposed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Protoplasma 168 (1992), S. 51-63 
    ISSN: 1615-6102
    Keywords: Cellulose microfibril formation ; Chlorophyta ; Coleochaete scutata ; Freeze fracture ; Plasma membrane ; Terminal complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cells of the charophycean alga,Coleochaete scutata active in cell wall formation were freeze fractured in the search for cellulose synthesizing complexes (TCs) since this alga is considered to be among the most advanced and a progenitor to land plant evolution. We have found a new TC which consists of two geometrically distinctive particle complexes complementary to one another in the plasma membrane and occasionally associated with microfibril impressions. In the E-fracture face is found a cluster of 8–50 closely packed particles, each with a diameter of 5–17 nm. Most of these particles are confined within an 80 nm circle. In the P-fracture face is found an 8-fold symmetrical arrangement of 10 nm particles circumferentially arranged around a 28 nm central particle. The TCs ofC. scutata are quite distinctive from the rosette/globule TCs of land plants. The 5.5×3.1 nm microfibril inC. scutata is also distinctive from the 3.5×3.5 nm microfibril typical of land plants. The phylogenetic implications of this unique TC in land plant evolution are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1615-6102
    Keywords: Cellulose formation ; 2,6-Dichlorobenzonitrile ; Freeze etching ; Plasma membrane ; Cellulose synthesizing enzyme complex ; Tinopal LPW ; Vaucheria hamata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effects of 2,6-dichlorobenzonitrile (DCB, a known inhibitor of cellulose synthesis) and Tinopal LPW (TPL, an agent which disrupts glucan crystallization) on the structure of cellulose synthesizing complexes (terminal complexes, TCs) in the xanthophycean algaVaucheria hamata were investigated. DCB (10 μM) inhibits nascent fibril formation from the TC subunit (based on the absence of impressions) although it does not alter the overall shape of the rectangular TC during the short treatment of 20 min. With a prolonged treatment (60 min), the arrangement of TC subunits becomes disordered, and particles generally exhibited as doublets of subunits are released from each other. DCB also interferes with the formation of the overall shape of the TC although it does not disturb the conversion into TC rows of the subunits (the zymogenic precursor of the TC) packed in the globules. A 15 min treatment with TPL (1 mM) destroys the TC integrity by reducing the subunits into small fragments or particulate aggregates. The particulate rows of the TC are interrupted at many points, and fragments and particulate aggregates are dispersed by prolonged treatment (45 min) with TPL. Unlike DCB, TPL inhibits the conversion of globule subunits into TC rows. New insights on the structural characteristics necessary for cellulose microfibril assembly and possible mechanisms for the biogenesis of theVaucheria TC come from these data.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0095-9898
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    BioEssays 17 (1995), S. 803-812 
    ISSN: 0265-9247
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Endosperm is emerging as a system for investigating the genetic control of wall placement and deposition in plant development. Development of endosperm progresses in distinct stages from a wall-less syncytial stage to a cellular stage that is entirely typical of plant meristems where the division plane is predicted by a preprophase band of microtubules (PPB) and cytokinesis is completed by formation of a cell plate in association with a phragmoplast. Four developmentally different types of walls, each associated with a different microtubule system, are sequentially produced: (1) free growing walls deposited in the absence of mitosis and phragmoplasts; (2) walls guided by cytoplasmic phragmoplasts formed adventitiously in the absence of mitosis; (3) walls formed by interzonal phragmoplasts in a cell cycle that lacks PPBs; and (4) wall deposition driven by interzonal phragmoplasts in a cycle that includes PPBs. We are using methods of differential screening to isolate cDNA clones corresponding in temporal and spatial pattern to the types of wall development, and are studying mutants for clues to the genetic controls of wall development.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 0741-0581
    Keywords: Scanning tunneling microscopy ; Langmuir-Blodgett films ; Covalent deposition ; Lipids ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Chemical selectivity of biosensors is derived from biological materials interfaced to the surface of transducing devices. Molecular recognition events lead to macroscopic function suitable for analytical measurements. The structure-function relationships of biochemical species at interfaces must be established to characterize and optimize biosensor operation. The techniques of ellipsometry, fluorescence microscopy, electron microscopy, and scanning tunneling microscopy are used to investigate the structure of monolayers and multilayers of proteins and lipids at interfaces that are prepared by Langmuir-Blodgett techniques and by self-assembly from bulk solution. The relative merits and limitations of the measurement techniques in the determination of aspects of interfacial structure are considered.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 6 (1987), S. 349-356 
    ISSN: 0741-0581
    Keywords: Lattice imaging ; Low dose technique ; Cellulose ; Crystallite size ; Digital image processing ; Formvar micronet ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The lattice imaging technique for cellulose, a typical electronbeam-sensitive material, was developed by using a conventional 120 kV electron microscope. Routine procedures for specimen preparation and high resolution, low dose electron microscopy are described in detail. A new, simple method was introduced for the preparation of a Formvar micronet to support the thin carbon film. The lattice imaging technique was successfully applied to algal celluloses as well as bacterial cellulose, which is composed of much smaller crystallites than the former. Digital image processing was found to be effective in enhancing the lattice images. The bacterial cellulose ribbon contained crystallites 10-25-nm wide, which is much greater than the basic unit of cellulose fibril extruded from the cell surface. This shows that unit fibrils can fasciate with each other, merging into a single crystallite.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...