Dextran causes aggregation of mitochondria and influences their oxidoreductase activities and light scattering

Lemeshko, Victor V.; Solano, Sigifredo; Rebolledo, Leonardo Andrés López; Rendón, Dairo Alonso; Ghafourifar, Pedram; Gómez, Luis A.

doi:10.1016/s0003-9861(03)00034-1

Cited by 15 publications

(5 citation statements)

References 23 publications

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“…According to the Guoy-Chapman theory, the thickness of the electrical double layer strongly depends on the ionic strength of the medium. The thickness of the electrical double layer in the 125 mM KCl solution is more than 3 times shorter than in 10 mM KCl (62). The average tension of the electric field near the membrane surface, within the calculated Debay-Hü ckel length ␦ 1 ϭ 0.84 nm for the KCl-medium, is 3.7 times higher than in the sucrose-medium (␦ 2 ϭ 3.09 nm), both buffered with 10 mM Hepes-Tris (Fig.…”

Section: Discussionmentioning

confidence: 92%

Mitochondria Permeabilization by a Novel Polycation Peptide BTM-P1

Lemeshko

Arias

Ordúz

2005

Journal of Biological Chemistry

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Bacillus thuringiensis subsp. medellin is known to produce the Cry11Bb protein of 94 kDa, which is toxic for mosquito larvae due to permeabilization of the plasma membrane of midgut epithelial cells. Earlier we found that a 2.8-kDa novel peptide BTM-P1, which was artificially synthesized taking into account the primary structure of Cry11Bb endotoxin, is active against several species of bacteria. In this work we show that BTM-P1 induces cyclosporin A-insensitive swelling of rat liver mitochondria in various salt solutions but not in the sucrose medium. Inorganic phosphate and Ca 2؉ significantly increased this effect of the peptide. The uncoupling action of BTM-P1 on oxidative phosphorylation was stronger in the potassiumcontaining media and correlated with a decrease of the inner membrane potential of mitochondria. In isotonic KNO 3 , KCl, or NH 4 NO 3 media, a complete drop of the inner membrane potential was observed at 1-2 g/ml of the peptide. The peptide-induced swelling was increased by energization of mitochondria in the potassium-containing media, but it was inhibited in the NaNO 3 , NH 4 NO 3 , and Tris-NO 3 media. All mitochondrial effects of the peptide were completely prevented by adding a single N-terminal tryptophan residue to the peptide sequence. We suggest a mechanism of membrane permeabilization that includes a transmembrane-and surface potential-dependent insertion of the polycation peptide into the lipid bilayer and its oligomerization leading to formation of ion channels and also to the mitochondrial permeability transition pore opening in a cyclosporin A-insensitive manner.

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Section: Discussionmentioning

confidence: 92%

Mitochondria Permeabilization by a Novel Polycation Peptide BTM-P1

Lemeshko

Arias

Ordúz

2005

Journal of Biological Chemistry

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“…One Mitochondria aggregation. Aggregation of liver mitochondria was studied as described (24) by using a light microscope (BalPlanBausch&Lomb, Rochester, NY) connected to a digital camera (Nikon Coolpix 4500, Nikon, Koga Ku, Japan). Mitochondria samples (3 Ag mitochondrial protein/AL) were placed on a Petroff-Hausser counting chamber with 20 Am cell depth (Hausser Scientific, Horsham, PA).…”

Section: Methodsmentioning

confidence: 99%

Tamoxifen Induces Oxidative Stress and Mitochondrial Apoptosis via Stimulating Mitochondrial Nitric Oxide Synthase

et al. 2007

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Tamoxifen is an anticancer drug that induces oxidative stress and apoptosis via mitochondria-dependent and nitric oxide (NO)-dependent pathways. The present report shows that tamoxifen increases intramitochondrial ionized Ca 2+ concentration and stimulates mitochondrial NO synthase (mtNOS) activity in the mitochondria from rat liver and human breast cancer MCF-7 cells. By stimulating mtNOS, tamoxifen hampers mitochondrial respiration, releases cytochrome c, elevates mitochondrial lipid peroxidation, increases protein tyrosine nitration of certain mitochondrial proteins, decreases the catalytic activity of succinyl-CoA:3-oxoacid CoA-transferase, and induces aggregation of mitochondria. The present report suggests a critical role for mtNOS in apoptosis induced by tamoxifen. [Cancer Res 2007;67(3):1282-90]

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“…74 Aliquots of the HEWL oligomers (20 μM final concentration) were added to mitochondrial homogenates and diluted with filtrated mitochondrial extraction buffer to 1 mg/ml, and scattered light was collected as described above for oligomer characterization, for 5 min at 30-s intervals.…”

Section: Aggregation Measurementmentioning

confidence: 99%