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
    Voltage-sensitive ion channel ofEscherichia coli (1989)
    Springer
    The journal of membrane biology 112 (1989), S. 267-275 
    Details
    ISSN: 1432-1424
    Keywords: Escherichia coli ; outer membrane ; ion channel ; patch clamp ; porin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary A voltage-sensitive, cation-selective ion channel ofEscherichia coli has been reconstituted into liposomes and studied with the patch-clamp method. The single channel conductance was 91 pS in symmetric solutions of 150mm KCl. Many channels were open most of the time, with frequent brief transitions to closed levels. Multiple conducting units could close and reopen simultaneously, and this apparent cooperativity in gating was increases with depolarizing voltages. Above a voltage threshold, the channels closed irreversibly, often in groups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01870957
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Activities of a Mechanosensitive Ion Channel in anE. Coli Mutant Lacking the Major Lipoprotein (1993)
    Springer
    The journal of membrane biology 131 (1993), S. 151-160 
    Details
    ISSN: 1432-1424
    Keywords: mechanosensitive channel ; outer membrane ; Escherichia coli/kw] ; lipoprotein ; membrane protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The activity of the mechanosensitive (MS) ion channels in membrane patches, excised fromE. coli spheroplasts, was analyzed using the patch-clamp technique. Outer membranes from a mutant lacking the major lipoprotein (Lpp) and its wildtype parent were examined. The MS-channel activities in the wild-type membrane rarely revealed substates at the time resolution used. These channels showed a stretch sensitivity indicated by the IISP (the suction for ane-fold increase in channel open probability) of 4.9 mm Hg suction. The MS-channel activities oflpp included a prominent substate and showed a weaker mechano-sensitivity with an 1/S p of 10.0 mm Hg. Whereas small amphipaths (chlorpromazine, trinitrophenol) or a larger amphipath (lysolecithin) all activated the MS channel in the wild-type membrane under minimal suction, only the larger lysolecithin could activate the MS channel in thelpp membranes. After lysolecithin addition, thelpp membrane became more effective in transmitting the stretch force to the MS channel, as indicated by a steepening of the Boltzmann curve. We discuss one interpretation of these results, in which the major lipoprotein serves as a natural amphipath inserted in the inner monolayer and the loss of this natural amphipath makes the bilayer less able to transmit the gating force.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02260105
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    A calcium-dependent potassium current is increased by a single-gene mutation inParamecium (1987)
    Springer
    The journal of membrane biology 98 (1987), S. 145-155 
    Details
    ISSN: 1432-1424
    Keywords: calcium-dependent K+ current ; mutant ; Paramecium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The membrane currents of wild typeParamecium tetraurelia and the behavioral mutantteaA were analyzed under voltage clamp. TheteaA mutant was shown to have a greatly increased outward current which was blocked completely by the combined use of internally delivered Cs+ and external TEA+. This, along with previous work (Satow, Y., Kung, C., 1976,J. Exp. Biol. 65:51–63) identified this as a K+ current. It was further found to be a calcium-activated K+ current since this increased outward K+ current cannot be elicited when the internal calcium is buffered with injected EGTA. The mutationpwB, which blocks the inward calcium current, also blocks this increased outward K+ current inteaA. This shows that this mutant current is activated by calcium through the normal depolarization-sensitive calcium channel. While tail current decay kinetic analysis showed that the apparent inactivation rates for this calcium-dependent K+ current are the same for mutant and wild type, theteaA current activates extremely rapidly. It is fully activated within 2 msec. This early activation of such a large outward current causes a characteristic reduction in the amplitude of the action potential of theteaA mutant. TheteaA mutation had no effect on any of the other electrophysiological parameters examined. The phenotype of theteaA mutant is therefore a general decrease in responsiveness to depolarizing stimuli because of a rapidly activating calcium-dependent K+ current which prematurely repolarizes the action potential.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01872127
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    A single amino acid substitution alters conductance and gating of OmpC porin ofEscherichia coli (1991)
    Springer
    The journal of membrane biology 119 (1991), S. 267-275 
    Details
    ISSN: 1432-1424
    Keywords: Escherichia coli ; ion channel ; mutant ; patch clamp ; porin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary We have reconstituted into liposomes outer-membrane fractions fromEscherichia coil strains which express OmpC porins with altered pore properties. Single-channel experiments were performed with the patch-clamp technique on blisters generated from the reconstituted liposomes. Our goal was to identify positively the activity pattern of OmpC in our reconstituted system. The properties of the parent strain were compared to those of a strain whose OmpC porin has a single amino acid substitution in a postulated transmembrane segment. The parent and the mutant strain each exhibit a cation-selective channel of high open probability and gating to closed levels of various amplitudes. However, the mutant channel appeared to be 9 to 30% larger in unit conductance. It tended to close and reopen most often in groups of three units, as opposed to two units in the parent channel. The results are discussed in terms of the observed phenotype and of their implication as to the structure-function relationship of the porin channels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01868731
    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...