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  • 1
    Electronic Resource
    Electronic Resource
    Movement of mitochondria in the ovarian trophic cord of Dysdercus intermedius (Heteroptera) resembles nerve axonal transport (1987)
    Springer
    Development genes and evolution 196 (1987), S. 407-413 
    Details
    ISSN: 1432-041X
    Keywords: Mitochondria transport ; Ovarian trophic cord ; Insect telotrophic ovariole ; Dysdercus intermedius ; AVEC-DIC microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The motile behaviour of mitochondria in the ovarian trophic cord of the red cotton bug, Dysdercus intermedius, was observed optically using video-enhanced differential interference contrast (AVEC-DIC) microscopy. The motion of 258 video-recorded mitochondria was analysed of which 10%–30% were found to move during the observation periods. Of the moving mitochondria 76% travelled towards the oocyte with an average velocity of 3.37 μm/ min, and 24% towards the tropharium with 2.84 μm/min. The movement was found to be basically of the saltatory type I as known from nerve axons characterized by the absence of directional reversal. In some cases short periods of interrupted motion of type II, i.e. with local oscillations, were observed. Individual mitochondria often showed velocity variations during the excursions. The hemipteran trophic cords are known to contain numerous parallel microtubules. As the observed type of mitochondrial motility resembles axonal transport, a modified transport hypothesis is presented for the microtubule-based motility of organelles in the nurse strands of telotrophic insect ovarioles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00399140
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  • 2
    Electronic Resource
    Electronic Resource
    Changes in the PCB world with new packaging technologies and the integration of passive components into the PCB (1998)
    Bradford : Emerald
    Circuit world 24 (1998), S. 6-9 
    Details
    ISSN: 0305-6120
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: New developments in the semi-conductor industry lead to higher I/O counts. Packaging is changing to new, smaller packages, like TCPs and CSPs, and the pitch density increases as well. For the fanout of such pages on the PCB, new design rules have to be applied. Blind via holes, sequential build-up technologies, new ways to form holes, new materials, a lot of questions for the PCB manufacturer. The integration of passive components, such as bypass capacitors and pull up and pull down resistors, into the PCB, go along with the next generation of packaging technology. This adds complexity to the printed circuit boards, leading to a new generation of PCBs that could better be called Integrated Component Boards (ICB). These boards offer a much higher price/area for the PCB manufacturer and at the same time give the OEM better performance with fewer assembly steps and much smaller units.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/03056129810197071
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  • 3
    Electronic Resource
    Electronic Resource
    Substance identification by quantitative characterization of oscillatory activity in murine spinal cord networks on microelectrode arrays (2004)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 19 (2004), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This paper presents a novel and comprehensive method to identify substances on the basis of electrical activity and is a substantial improvement for drug screening. The spontaneous activity of primary neuronal networks is influenced by neurotransmitters, ligands, and other substances in a similar fashion as known from in vivo pharmacology. However, quantitative methods for the identification of substances through their characteristic effects on network activity states have not yet been reported. We approached this problem by creating a database including native activity and five drug-induced oscillatory activity states from extracellular multisite recordings from microelectrode arrays. The response profiles consisted of 30 activity features derived from the temporal distribution of action potentials, integrated burst properties, calculated coefficients of variation, and features of Gabor fits to autocorrelograms. The different oscillatory states were induced by blocking neurotransmitter receptors for: (i) GABAA; (ii) glycine; (iii) GABAA and glycine; (iv) all major synaptic types except AMPA, and (v) all major synapses except NMDA. To test the identification capability of the six substance-specific response profiles, five blind experiments were performed. The response features from the unknown substances were compared to the database using proximity measures using the normalized Euclidian distance to each activity state. This process created six identification coefficients where the smallest correctly identified the unknown substances. Such activity profiles are expected to become substance-specific ‘finger prints’ that classify unique responses to known and unknown substances. It is anticipated that this kind of approach will help to quantify pharmacological responses of networks used as biosensors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.0953-816X.2004.03373.x
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  • 4
    Electronic Resource
    Electronic Resource
    Actin-dependent organelle movement in squid axoplasm (1992)
    [s.l.] : Nature Publishing Group
    Nature 356 (1992), S. 722-725 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] To study the role of actin filaments in fast axonal transport, we developed a procedure that allowed actin filaments to form an extensive network near the bulk axoplasm extruded from squid giant axon. Axoplasm was extruded into dissociation buffer and the distribution of actin filaments on the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/356722a0
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  • 5
    Electronic Resource
    Electronic Resource
    Fluorescence microscopy and three-dimensional imaging of the porcine corneal keratocyte network (1997)
    Springer
    Graefe's archive for clinical and experimental ophthalmology 235 (1997), S. 773-779 
    Details
    ISSN: 1435-702X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract • Background: Little is known about the spatial arrangement and the corresponding morphometric data describing the living keratocyte network. For determination of alterations in corneal diseases it is crucial to know the morphology of the keratocyte network in the healthy state. Porcine cornea was used as a model tissue because il allows the study of species differences. • Methods: Corneas from freshly enucleated pig eyes were stained with calcein AM and ethidium homodimer and examined by confocal laser scanning microscopy. High-resolution fluorescence images were used for three-dimensional reconstructions from which cell density and volume density were determined by computer-aided morphometry. • Results: Three keratocyte subpopulations were distinguished and visualized in their spatial arrangement. Significant differences with respect to both shape and fluorescence intensity distribution of the cell bodies were found. Cell volume density was 7.7% in the anterior stroma, 13.7% in the central stroma and 11.8% in the posterior stroma. • Conclusion: The technique described allowed good visualization of the spatial arrangement of the keratocyte network. Combined with morphometric methods, the analysis of the state of the cornea yields a quantitative description. The method is expected to be useful for the determination of morphological alterations in corneal disease or following surgical treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02332862
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  • 6
    Electronic Resource
    Electronic Resource
    Towards a new classification of intracellular particle movements based on quantitative analyses (1986)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 6 (1986), S. 128-135 
    Details
    ISSN: 0886-1544
    Keywords: motion analysis ; axonal transport ; cytoplasmic transport ; Brownian motion ; AVEC-DIC microscopy ; saltatory particle motion ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A survey study of organelle movements in a variety of cell types of plant and animal origin was made with the aid of video-enhanced contrast, differential interference contrast (AVEC-DIC) microscopy followed by fine analysis of the motile behavior of the individual organelles. We found that there exists besides Brownian motion a wide spectrum of active motions in cells, i.e. motion that is directionally biased through the expenditure of metabolic energy. The types of active motion seen range from a continuous motion (sometimes appearing as streaming) in plant cells and neurons to various types of less ordered and less well directed motion. We did not see any clear-cut qualitative difference between plant and animal cells or between systems presumed to be actin- and microtubule-based. A preliminary classification of the types of active motion is presented. The ongoing research activities, which aim at a more precise definition of the different types of motion by a set of quantitative parameters, are described, and the progress made so far is reported.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970060210
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  • 7
    Electronic Resource
    Electronic Resource
    Substructure of sidearms on squid axoplasmic vesicles and microtubules visualized by negative contrast electron microscopyPart of this work was performed at the Marine Biological Laboratory, Woods Hole, MA 02543. (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 20-30 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We present a high-resolution electron microscopic study of the sidearms on microtubules and vesicles that are suggested to form the crossbridges which produce the microtubule-based vesicle transport in squid axoplasm. The sidearms were found attached to the surfaces of the anterogradely transported vesicles in the presence of ATP. These sidearms were made of one to three filaments of uniform diameter. Each filament measured 5-6 nm in width and 30-35 nm in length. The filaments in some of the sidearms had splayed apart by pivoting at their base, thereby assuming a “V” shape. The spread configuration illustrated the independence of the individual filaments. The filaments in other sidearms were closely spaced and oriented parallel to each other, a pattern called the compact configuration. In axoplasmic buffer containing AMP-PNP, structures indistinguishable from the filaments of the sidearms on the vesicles were observed attached to microtubules. Pairs of filaments, thought to represent the basic functional unit, were observed attached to adjacent protofilaments of the microtubules by their distal tips. These data support a model of vesicle movement in which a pair of filaments within a sidearm forms two crossbridges and moves a vesicle by “walking” along the protofilaments of the microtubule.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070104
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  • 8
    Electronic Resource
    Electronic Resource
    Effects of vanadate on the assembly and disassembly of purified tubulin (1986)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 6 (1986), S. 314-323 
    Details
    ISSN: 0886-1544
    Keywords: vanadate ; microtubules ; tubulin polymerization ; taxol ; dynein ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Sodium-orthovanadate (100-700 μM) added to purified pig brain microtubule protein (molar ratios 13-90 moles vanadate/mole tubulin) inhibits to a considerable extent the assembly (up to 65%) and the disassembly rates (up to 60%) of microtubules, as determined by turbidimetry. Vanadate added to preformed microtubules did not appreciably alter the turbidity level of the samples, however, the disassembly rates were decreased in the same manner as when vanadate was added prior to polymerization. Microtubule protein kept on ice for 3-6 hours became more susceptible to vanadate than freshly prepared protein. The effect of vanadate was independent of the GTP concentration at which the polymerization assays were performed (0.025 to 1 mM GTP). In the presence of taxol, which increases the rate and extent of microtubule formation, vanadate had no effect on assembly rates. Disassembly was inhibited, however, much less than in the presence of vanadate alone. Electron microscopy and polyacrylamide gel electrophoresis did not reveal differences between microtubules prepared in the presence or in the absence of vanadate. This is consistent with the notion that vanadate does not interfere with the interaction between tubulin and the high-molecular weight microtubule-associated proteins. Apparently vanadate brings about an allosteric change of the microtubule protein(s) resulting in the abnormal polymerization kinetics of tubulin found in our study. The above results may be relevant for studies where the effects of vanadate on intracellular motility are interpreted as being solely due to a specific inhibition of ATPases.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970060308
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  • 9
    Electronic Resource
    Electronic Resource
    Movement of axoplasmic organelles on actin filaments from skeletal muscle (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 231-242 
    Details
    ISSN: 0886-1544
    Keywords: squid axoplasm ; organelle movement ; calmodulin ; actin filaments ; axonal transport ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: It was recently shown that, in addition to the well-established microtubule-dependent mechanism, fast transport of organelles in squid giant axons also occurs in the presence of actin filaments [Kuznetsov et al., 1992, Nature 356:722-725]. The objectives of this study were to obtain direct evidence of axoplasmic organelle movement on actin filaments and to demonstrate that these organelles are able to move on skeletal muscle actin filaments. Organelles and actin filaments were visualized by video-enhanced contrast differential interference contrast (AVEC-DIC) microscopy and by video intensified fluorescence microscopy. Actin filaments, prepared by polymerization of monomeric actin purified from rabbit skeletal muscle, were stabilized with rhodamine-phalloidin and adsorbed to cover slips. When axoplasm was extruded on these cover slips in the buffer containing cytochalasin B that prevents the formation of endogenous axonal actin filaments, organelles were observed to move at the fast transport rate. Also, axoplasmic organelles were observed to move on bundles of actin filaments that were of sufficient thickness to be detected directly by AVEC-DIC microscopy. The range of average velocities of movement on the muscle actin filaments was not statistically different from that on axonal filaments. The level of motile activity (number of organelles moving/min/field) on the exogenous filaments was less than on endogenous filaments probably due to the entanglement of filaments on the cover slip surface. We also found that calmodulin (CaM) increased the level of motile activity of organelles on actin filaments. In addition, CaM stimulated the movement of elongated membranous organelles that appeared to be tubular elements of smooth endoplasmic reticulum or extensions of prelysosomes. These studies provide the first direct evidence that organelles from higher animal cells such as neurons move on biochemically defined actin filaments. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970280306
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  • 10
    Electronic Resource
    Electronic Resource
    Dynamic instability and motile events of native microtubules from squid axoplasm (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 10 (1988), S. 285-295 
    Details
    ISSN: 0886-1544
    Keywords: organelle movement ; microtubule assembly/disassembly ; motion analysis ; MAPs ; force generation ; axonal transport ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Native microtubules from extruded axoplasm of squid giant axons were used as a paradigm to characterize the motion of organelles along free microtubules and to study the dynamics of microtubule length changes. The motion of large round organelles was visualized by AVEC-DIC microscopy and analyzed at a temporal resolution of 10 frames per second. The movements were smooth and showed no major changes in velocity or direction. During translocation, the organelles paused very rarely. Superimposed on the rather constant mean velocity was a velocity fluctuation, which indicated that the organelles are subject to considerable thermal motion during translocation. Evidence for a regular low-frequency oscillation was not found. The thermal motion was anisotropic such that axial motion was less restricted than lateral motion. We conclude that the crossbridge connecting the moving organelle to the microtubule has a flexible region that behaves like a hinge, which permits preferential movement in the direction parallel to the microtubule. The dynamic changes in length of native microtubules were studied at a temporal resolution of 1 Hz. About 98% of the native microtubules maintained their length (“stable” microtubules), while 2% showed phases of growing and/or shrinking typical for dynamic instability (“dynamic” microtubules). Gliding and organelle motion were not influenced by dynamic length changes. Transitions between growing and shrinking phases were low-frequency events (1-10 minutes per cycle). However, a new type of microtubule length fluctuation, which occurred at a high frequency (a few seconds per cycle), was detected. The length changes were in the 1-3 μm range. The latter events were very prominent at the (+) ends. It appears that the native axonal microtubules are much more stable than the purified microtubules and the microtubules of cultured cells that have been studied thus far. Potential mechanisms accounting for the three states of microtubule stability are discussed. These studies show that the native microtubules from squid giant axons are a very useful paradigm for studying microtubule-related motility events and microtubule dynamics.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970100133
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