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
    Dynamics of actin and alpha-actinin in the tails of Listeria monocytogenes in Infected PtK2 Cells (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 346-358 
    Details
    ISSN: 0886-1544
    Keywords: Listeria monocytogenes ; actin ; alpha-actinin ; actin polymerization ; assembly ; disassembly ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Listeria monocytogenes can penetrate and multiply within a variety of cell types, including the PtK2 kidney epithelial line. Once released within the cytoplasm, L. monocytogenes acquires the capacity for rapid movement through the host cell [Dabiri et al., 1990: Proc. Natl. Acad. Sci. 87:6068-6072]. In the process, actin monomers are inserted in proximity to one end of the bacterium, forming a column or tail of actin filaments [Sanger et al., 1992: Infect. Immun. 60:3609-3619]. The rate of new actin filament growth correlates closely with the speed of bacterial migration. In this study we have used fluorescently labeled actin and alpha-actinin to monitor the movement and turnover rate of actin and alpha-actinin molecules in the tails. The half-lives of the actin and alpha-actinin present in the tails are approximately the same: actin, 58.7 sec; alpha-actinin, 55.3 sec. The half-life of alpha-actinin surrounding a dividing bacterium was 30 sec, whereas its half-life in the tails that formed behind the two daughter cells was about 20-30% longer. We discovered that the speeds of the bacteria are not constant, but show aperiodic episodes of decreased and increased speeds. There is a fluctuation also in the intensities of the fluorescent probes at the bacterium/tail interface, implying that there is a fluctuation in the number of actin filaments forming there. There was no strong correlation, however, between these fluctuating intensities and changes in speed of the bacteria. These measurements suggest that while actin polymerization at the bacterial surface is coupled to the movement of the bacterium, the periodic changes in intracellular motility are not a simple function of the number of actin filaments nucleating at the bacterial surfaces. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970280408
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Listeria monocytogenes intracellular migration: Inhibition by profilin, vitamin D-binding protein and DNase I (1995)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 30 (1995), S. 38-49 
    Details
    ISSN: 0886-1544
    Keywords: Listeria monocytogenes ; actin ; profilin ; DNase I ; vitamin D-binding protein ; phalloidin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Infection of host cells by Listeria monocytogenes results in the recruitment of cytoplasmic actin into a tail-like appendage that projects from one end of the bacterium. Each filamentous actin tail progressively lengthenes, providing the force which drives the bacterium in a forward direction through the cytoplasm and later results in Listeria cell-to-cell spread. Host cell actin monomers are incorporated into the filamentous actin tail at a discrete site, the bacterial-actin tail interface. We have studied the consequences of microinjecting three different actin monomer-binding proteins on the actin tail assembly and Listeria intracellular movement. Introduction of high concentrations of profilin (estimated injected intracellular concentration 11-22 m̈M) into infected PtK2 cells causes a marked slowing of actin tail elongation and bacterial migration. Lower intracellular concentrations of two other injected higher affinity monomer-sequenstering proteins, Vitamin D-binding protein (DBP; 1-2 m̈M) and DNase I (6-7 m̈M) completely block bacterial-induced actin assembly and bacterial migration. The onset of inhibition by each protein is gradual (10-20 min) indicating that the mechanisms by which these proteins interfere with Listeria-induced actin assembly are likely to be complex. To exclude the possibility that Listeria recruits preformed actin filaments to generate the tails and that these monomer-binding proteins act by depolymerizing such performed actin filaments, living infected cells have been injected with fluorescently labeled phalloidin (3 m̈M). Although the stress fibers are labeled, no fluorescent phalloidin is found in the tails of the moving bacteria. These results demonstrate that Listeria-induced actin assembly in PtK2 cells is the result of assembly of actin monomers into new filaments and that Listeria's ability to recruit polymerization competent monomeric actin is very sensitive to the introduction of exogenous actin monomer-binding proteins. © 1995 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970300106
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Organization and structure of actin filament bundles in Listeria-infected cells (1995)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 30 (1995), S. 229-246 
    Details
    ISSN: 0886-1544
    Keywords: Listeria monocytogenes ; fluorescence polarization ; actin ; confocal microscopy ; mutant ; infections ; PtK2 cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: During its motion inside host cells, Listeria monocytogenes promotes the formation of a column of actin filaments that extends outward from the distal end of the moving bacterium. The column is constructed of short actin filaments that polymerize at the bacteria-column interface. To get a measure of filament organization in the column, Listeria grown in cultured PtK2 cells were studied with steady state fluorescence polarization, confocal microscopy, and whole cell intermediate voltage electron microscopy. Although actin filament ordering was higher in nearby stress fibers than in the Listeria-associated actin, four distinct areas of ordering could be observed in fluorescence polarization ratio images of bacteria: (1) the surface of the bacteria, (2) the cytoplasm next to the bacteria, (3) the outer shell of the actin column, and (4) the core of the column. Filaments were preferentially oriented parallel to the long axis of the column with highest ordering along the long axis of the bacterial surface and in the shell of the tail. The lowest ordering was in the core (where filaments are possibly also shorter with respect to the cup and the shell), whereas in the adjacent cytoplasm, filaments were oriented perpendicular to the column. A mutant of Listeria that can polymerize actin around itself but cannot move intracellularly does not have its actin organized along the bacterial surface. Thus the alignment of the actin filaments along the bacterial surfaces may be important for the intracellular movement. These conclusions are also supported by confocal microscopy and whole mount electron microscopic data that also reveal that actin filaments can be deposited asymmetrically around the long axis of the bacteria, a distribution that may affect the direction of motility of Listeria monocytogenes inside infected cells. © 1995 Wiley-Liss, Inc.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970300307
    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...