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Halnes, Geir; Tennøe, Simen; Einevoll, Gaute; Haug, Trude; Weltzien, Finn-Arne & Hodne, Kjetil
(2019).
A computational model of the spontaneous activity of gonadotrophin-releasing cells in the teleost fish models.
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Mobråten, Kaia; Haug, Trude M; Kleiveland, Charlotte Ramstad & Lea, Tor Erling
(2013).
Omega-3 and omega-6 PUFAs both activated GPR120 in Caco2 cells.
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Sand, Sverre L.; Nissen-Meyer, Jon; Sand, Olav & Haug, Trude M
(2011).
The cationic peptide plantaricin A produced by Lactobacillus plantarum permeabilizes eukaryotic cell membranes by a mechanism dependent on negative surface charge linked to glycosylated membrane proteins.
Acta Physiologica.
ISSN 1748-1708.
202.
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Haug, Trude M; Sand, Sverre L.; Phung, Danh; Hardy, Simpn P. & Sand, Olav
(2009).
The Bacillus cereus Nhe enterotoxin forms gigantic channels in cell membranes.
Acta Physiologica.
ISSN 1748-1708.
196.
Vis sammendrag
The Nhe enterotoxin was discovered following a large food-poisoning outbreak in Norway in 1995, and consists of three separate proteins: Nhe-A, -B, and -C. The Nhe complex induces cell lysis in clonal epithelial cell lines (Vero and Caco2), and forms channels of 200-700 pS conductance in planar lipid bilayers (Fagerlund et al. 2008). Electrophysiological effects of Nhe on cell membranes have previously not been examined. We have studied the membrane effects of Nhe on Vero cells and clonal pituitary cells (GH4 cells) by patch clamp recordings and microfluorometric (fura-2) monitoring of the cytosolic Ca2+ level ([Ca2+]i ) and fluorochrome concentration. Cell lysis was assessed by measuring the release of lactate dehydrogenase (LDH). Within 30 min, preparations of Nhe from 5 hr culture supernatants of B. cereus NVH75/95 induced massive LDH release, i.e., 90-100 % of maximum (triton X-100) in both cell types. Whole-cell voltage clamp recordings revealed Nhe-induced insertion of gigantic channels after a delay of 1-3 min. The mean single channel conductance was estimated to 8 nS, which is more than 10 times the mean channel conductance in planar lipid bilayers. The reversal potential of the channel currents was close to 0 mV, indicating an unselective channel. To our knowledge, this is the highest channel conductance reported in cell membranes under quasi-physiological conditions. Nhe also increased [Ca2+]i abruptly to saturating levels after a similar delay, followed by a gradual loss of fluorochrome from the cytosol. We conclude that the Nhe toxin complex induces cell lysis by forming large conductance channels in the plasma membrane of target epithelia.
Reference: Fagerlund A., Lindbäck T., Storset A.K., Granum P.E. and Hardy S.P. 2008. Microbiology 154, 693-704.
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Andersland, Kristin; Johansen, Guro Five; Haug, Trude M & Sand, Olav
(2008).
THE ANTIMICROBIAL PEPTIDE PLANTARICIN A PERMEABILIZES LIVER AND KIDNEY CELLS.
Acta Physiologica.
ISSN 1748-1708.
193.
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Haug, Trude M; Hodne, Kjetil; Weltzien, Finn-Arne & Sand, Olav
(2007).
Signaling properties of teleost gonadotropes with a first study from atlantic cod.
Acta Physiologica.
ISSN 1748-1708.
190.
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Sand, Sverre L.; Haug, Trude M; Nissen-Meyer, Jon & Sand, Olav
(2006).
Clonal rat anterior pituitary cells (GH4 cells) are permeabilized by plantaricin A, a peptide pheromone produced by Lactobacillus plantarum.
SFN Abstract Viewer/Itinerary Planner.
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Antimicrobial peptides and proteins, generally referred to as bacteriocins, are produced by numerous strains of bacteria. Plantaricin A (PlnA) is a 26-mer peptide pheromone that induces bacteriocin production in the strain from which it is released, Lactobacillus plantarum C11. Although pheromone activity is the prime biological function of PlnA, the peptide also has membrane-permeabilizing strain-specific antibacterial activity.
The pheromone activity of PlnA depends on its binding to specific receptors, preceded by a non-chiral interaction with the target cell membrane. The latter mechanism is presumably responsible for the membrane-permeabilizing effect on sensitive strains.
We have studied the effect of PlnA on the GH4 cell line using the patch clamp techniques. This neoplastic cell line is derived from a rat anterior pituitary tumor, and is commonly used as a model system for anterior pituitary cells. Whole-cell current clamp recordings revealed massive membrane permeabilization within 5 s after exposure to 10-100 µM PlnA. The membrane depolarized to abut 0 mV and the membrane resistance decreased to a mere fraction of the initial value after less than 1 min. Recordings from outside-out patches during exposure to 10 µM PlnA showed that the induced membrane current reversed at 0 mV, indicating an unspecific conductance increase. The D-form of the peptide, composed of only D-amino acids, was as effective as the L-form, indicating that PlnA exerts its membrane-permeabilizing effect through a non-chiral mechanism. Recordings from inside-out patches during exposure of the internal leaflet of the cell membrane to 1 mM PlnA showed both unaltered membrane conductance and BK channel activity. These results suggest that the peptide does not interfere with the membrane integrity when the inner leaflet is exposed. Surprisingly, the normal counterparts of the GH4 cell line, primary cell cultures of rat anterior pituitary, were insensitive to the peptide. Even at a concentration of 1 mM, PlnA had no detectable effects on the membrane conductance of normal anterior pituitary cells in any of the patch clamp configurations. Thus, the peptide seems to differentiate not only between membrane leaflets, but also between plasma membranes. This characteristic makes the membrane permeabilizing effects of PlnA particularly intriguing.
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Sand, Sverre Larsstuvold; Haug, Trude M; Fimland, Gunnar; Nissen-Meyer, Jon & Sand, Olav
(2006).
Membrane-permeabilizing effects of the bacterial peptide Plantaricin A on rat anterior pituitary cells.
Acta Physiologica.
ISSN 1748-1708.
187.
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Haug, Trude M; Hodne, Kjetil; Weltzien, Finn-Arne & Sand, Olav
(2006).
Electrophysiological properties of pituitary cells in primary cultures from atlantic cod (Gadus morhua).
Acta Physiologica.
ISSN 1748-1708.
187.
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Kristiansen, Per Eugen; Sand, Sverre; Haug, Trude M; Sand, Olav; Fimland, Gunnar & Zhao, Hongxia
[Vis alle 10 forfattere av denne artikkelen]
(2006).
Structure and Mode of Action of the Membrane-Permeabilizing Antimicrobial Peptide Pheromone Plantaricin A.
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Sand, Olav; Haug, Trude M & Mørk, Halvor
(2005).
Electrophysiological properties of anterior pituitary cells.
Acta Physiologica Scandinavica.
ISSN 0001-6772.
183.
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Mørk, Halvor; Haug, Trude M & Sand, Olav
(2004).
Contribution of different Ca2+-activated K+-channels to the first phase of the TRH response in clonal anterior pituitary cells (GH4 cells).
Acta Physiologica Scandinavica.
ISSN 0001-6772.
181.
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Haug, Trude M; Hafting, Torkel & Sand, Olav
(2004).
Contribution of BK channels to the resting conductance and the second phase of the response to TRH in anterior pituitary cells (GH4C1cells).
Acta Physiologica Scandinavica.
ISSN 0001-6772.
181.
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Haug, Trude M; Hafting-Fyhn, Torkel & Sand, Olav
(2003).
Contribution of BK channels to the second phase of the response to TRH in anterior pituitary cells (GH4 cells).
SFN Abstract Viewer/Itinerary Planner.
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Haug, Trude M; Ciani, Sergio; Toro, Ligia; Stefani, Enrico & Olcese, Riccardo
(2003).
Neutralization of the aspartate in the GYGD pore sequence affects gating properties in BKCa channels.
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Haug, Trude M; Olcese, Riccardo; Ciani, Sergio; Toro, Ligia & Stefani, Enrico
(2002).
Regulation of inward potassium flow by a negative residue in the outer vestibule of the MaxiK channel pore.
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Stefani, Enrico; Haug, Trude M; Ciani, Sergio; Toro, Ligia & Olcese, Riccardo
(2002).
Conduction of K ions through BKCa channels is enhanced by a negatively charged residue near the pore (D292).
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Olcese, Riccardo; Zhu, Ning; Haug, Trude M; Toro, Ligia & Stefani, Enrico
(2002).
Conformational changes in BK(Ca) channel during channel opening and closing revealed by optical methods.
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Haug, Trude M; Olcese, Riccardo; Zhu, Ning; Toro, Ligia & Stefani, Enrico
(2001).
Reduced Ca2+-sensitivity in the D292N mutant of hSlo potassium channel pore.
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Olcese, Riccardo; Zhu, Ning; Haug, Trude M; Toro, Ligia & Stefani, Enrico
(2001).
Voltage dependent conformational changes in MaxiK channels assessed by fluorescent labeling.
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Storm, Johan Fredrik; Pedarzani, P. & Haug, Trude M
(2000).
Modulation of K+ channels in hippocampal neurons: transmitters acting via cyclic AMP enhance the excitability through kinase-dependent and -independent modulation of AHP- and h-channels.
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Haug, Trude M & Storm, Johan Fredrik
(1998).
Peptidergic modulation via protein kinase A of the slow Ca2+-dependent K+ current IAHP in hippocampal pyramidal cells.
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Haug, Trude M & Sand, Olav
(1997).
BK-channels in cell-attached patches of clonal pituitary cells (GH4 cells).
Abstracts - Society for Neuroscience.
ISSN 0190-5295.
23(2).
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Haug, Trude M & Sand, Olav
(1996).
Activation of BK-channels in intact clonal pituitary cells.
Acta Physiologica Scandinavica.
ISSN 0001-6772.
157.
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Haug, Trude M & Storm, Johan Frederik
(1999).
Ca2+ -activated and ATP-sensitive potassium channels in endocrine cells and neurons.
Unipub forlag.